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[PATCH v48 5/7] Doc part of shared-memory based stats collector. 228+ messages / 2 participants [nested] [flat]
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v43 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 62711ee83f..fff553c6a5 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9223,9 +9223,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 4b60382778..e6bf21b450 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7299,11 +7299,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7319,14 +7319,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7357,9 +7356,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8420,7 +8419,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8432,9 +8431,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 19d7bd2b28..3a1dc17057 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2329,12 +2329,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 52a69a5366..a9cb25e3af 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -637,7 +627,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1074,10 +1064,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1832,6 +1818,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5989,9 +5979,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 0aa35cf0c3..ad105cb2a6 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Dec_11_16_50_03_2020_915)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v43-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v44 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index d988636046..b9e4eb1040 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 4b60382778..e6bf21b450 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7299,11 +7299,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7319,14 +7319,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7357,9 +7356,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8420,7 +8419,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8432,9 +8431,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 19d7bd2b28..3a1dc17057 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2329,12 +2329,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 52a69a5366..a9cb25e3af 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -637,7 +627,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1074,10 +1064,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1832,6 +1818,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5989,9 +5979,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 0aa35cf0c3..ad105cb2a6 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Mon_Dec_21_17_16_20_2020_608)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v44-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v36 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 508bea3bc6..d30491d4f6 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9208,9 +9208,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index c4ba49ffaf..530f41c194 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7190,11 +7190,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7210,14 +7210,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7248,9 +7247,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8311,7 +8310,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8323,9 +8322,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index beb309e668..45ec7ce68f 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2366,12 +2366,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 673a0e73e4..dbf439891d 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -620,7 +610,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1057,10 +1047,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1815,6 +1801,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5738,9 +5728,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 0b2e2de87b..ad88efdfee 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1288,11 +1288,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.4 ----Next_Part(Tue_Sep__8_17_55_57_2020_197)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v36-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v37 5/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index de9bacd34f..69db5afc94 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9209,9 +9209,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 8eabf93834..cc5dc1173f 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7192,11 +7192,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7212,14 +7212,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7250,9 +7249,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8313,7 +8312,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8325,9 +8324,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index beb309e668..45ec7ce68f 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2366,12 +2366,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 4e0193a967..7a04d58a1a 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -620,7 +610,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1057,10 +1047,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1815,6 +1801,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5738,9 +5728,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index e09ed0a4c3..71bb24accf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1290,11 +1290,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.4 ----Next_Part(Fri_Sep_25_09_27_26_2020_419)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v37-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v38 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index de9bacd34f..69db5afc94 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9209,9 +9209,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 8eabf93834..cc5dc1173f 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7192,11 +7192,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7212,14 +7212,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7250,9 +7249,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8313,7 +8312,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8325,9 +8324,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 42f01c515f..ec02e72dc0 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2367,12 +2367,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 4e0193a967..7a04d58a1a 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -620,7 +610,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1057,10 +1047,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1815,6 +1801,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5738,9 +5728,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index e09ed0a4c3..71bb24accf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1290,11 +1290,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.4 ----Next_Part(Thu_Oct__1_09_07_22_2020_252)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v38-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v39 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3927b1030d..87336e81ff 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9210,9 +9210,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index ee914740cc..b4537fc460 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7192,11 +7192,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7212,14 +7212,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7250,9 +7249,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8313,7 +8312,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8325,9 +8324,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 86da84fce7..24a42d1f44 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 171ba7049c..7c64cbc667 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -628,7 +618,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1065,10 +1055,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1823,6 +1809,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5797,9 +5787,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 1400cf8775..fd6c92b347 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1286,11 +1286,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.4 ----Next_Part(Tue_Oct__6_10_06_44_2020_382)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v39-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v40 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 5fb9dca425..884dc12340 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9211,9 +9211,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index f043433e31..b98d47189f 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7276,11 +7276,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7296,14 +7296,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7334,9 +7333,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8397,7 +8396,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8409,9 +8408,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 19d7bd2b28..3a1dc17057 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2329,12 +2329,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 98e1995453..4c1880bbc0 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -637,7 +627,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1074,10 +1064,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1832,6 +1818,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5950,9 +5940,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 0aa35cf0c3..ad105cb2a6 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.4 ----Next_Part(Wed_Nov__4_17_39_10_2020_208)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v40-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v41 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 5fb9dca425..884dc12340 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9211,9 +9211,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index f043433e31..b98d47189f 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7276,11 +7276,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7296,14 +7296,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7334,9 +7333,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8397,7 +8396,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8409,9 +8408,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 19d7bd2b28..3a1dc17057 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2329,12 +2329,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 98e1995453..4c1880bbc0 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -637,7 +627,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1074,10 +1064,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1832,6 +1818,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5950,9 +5940,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 0aa35cf0c3..ad105cb2a6 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.4 ----Next_Part(Fri_Nov__6_09_27_56_2020_738)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v41-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v42 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 569841398b..d5b26a51df 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9211,9 +9211,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index f043433e31..b98d47189f 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7276,11 +7276,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7296,14 +7296,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7334,9 +7333,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8397,7 +8396,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8409,9 +8408,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 19d7bd2b28..3a1dc17057 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2329,12 +2329,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 98e1995453..4c1880bbc0 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -637,7 +627,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1074,10 +1064,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1832,6 +1818,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5950,9 +5940,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 0aa35cf0c3..ad105cb2a6 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.4 ----Next_Part(Wed_Nov_11_10_07_22_2020_796)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v42-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v34 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 128 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 700271fd40..fad9f94ddb 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9177,9 +9177,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 4eef970d41..8da4b60fe9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7113,11 +7113,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7133,14 +7133,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7171,9 +7170,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8234,7 +8233,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8246,9 +8245,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 65c3fc62a9..56ef2f56f6 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2368,12 +2368,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 321a0f4bb1..374403a25a 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -620,7 +611,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1060,10 +1051,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1788,6 +1775,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5733,9 +5724,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 197b5c0d70..8e205f5b2b 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1289,11 +1289,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Mon_Jun__1_18_00_01_2020_089)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v34-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v35 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 128 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 700271fd40..fad9f94ddb 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9177,9 +9177,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index aca8f73a50..679135c6b6 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7113,11 +7113,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7133,14 +7133,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7171,9 +7170,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8234,7 +8233,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8246,9 +8245,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 65c3fc62a9..56ef2f56f6 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2368,12 +2368,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 89662cc0a3..4973d69cfc 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -620,7 +611,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1060,10 +1051,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1788,6 +1775,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5739,9 +5730,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 2f0807e912..ce5c60de10 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1287,11 +1287,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Mon_Jun__8_17_32_04_2020_489)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v35-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v33 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 29 +++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 128 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 88 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 9d8fa0bec3..4d93722af5 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9175,9 +9175,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 9f2a4a2470..b84e3f27b2 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7110,11 +7110,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7130,14 +7130,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7168,9 +7167,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8230,7 +8229,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previous activity statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8243,7 +8242,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in + activity statistics. The total number of heap tuples is stored in the index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 44cc5d2116..c958337ac8 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2366,12 +2366,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 87502a49b6..94f5d21243 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -603,7 +594,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1038,10 +1029,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of the statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting for WAL from a stream at recovery.</entry> @@ -1940,6 +1927,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>XidGenLock</literal></entry> <entry>Waiting to allocate or assign a transaction id.</entry> </row> + <row> + <entry><literal>activity_statistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>async</literal></entry> <entry>Waiting for I/O on an async (notify) buffer.</entry> @@ -5493,9 +5484,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 197b5c0d70..8e205f5b2b 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1289,11 +1289,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Fri_May_15_17_30_36_2020_111)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v33-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v45 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 7c0a673a8d..f6c80df988 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index dcb25dc3cd..7507783eaa 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Jan__8_10_24_34_2021_185)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v45-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v46 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 3a2266526c..4d8b92df72 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9234,9 +9234,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index efc382cb8d..6c620469eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2338,12 +2338,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3cdb1aff3c..afa8c35127 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -5996,9 +5986,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_14_15_14_25_2021_903)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v46-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v47 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 34 ++++---- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 90 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 43d7a1ad90..179607fd5a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9245,9 +9245,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 82864bbb24..b0c25c9c5c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7327,11 +7327,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7347,14 +7347,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7385,9 +7384,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8485,7 +8484,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8497,9 +8496,10 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; the index contains deleted pages that can be recycled during cleanup. Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> - fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in - the index meta-page. Note that the meta-page does not include this data + + fraction of the total number of heap tuples in the previously + collected statistics. The total number of heap tuples is stored in the + index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and subsequent <command>VACUUM</command> cycles detect no dead tuples. diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index dc263e4106..f3ff7b6b6a 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2365,12 +2365,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index f05140dd42..9c9dedb6b1 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6073,9 +6063,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Thu_Jan_21_12_03_48_2021_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v57 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 5c9f4af1d5..795c042a3d 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9271,9 +9271,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 8603cf3f94..99a55d276d 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7398,11 +7398,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7418,14 +7418,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7456,9 +7455,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Thu_Mar_18_16_56_02_2021_947)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v57-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v48 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..a2dad90c91 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6071,9 +6061,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Fri_Mar__5_17_18_56_2021_497)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v49 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 967de73596..753b1ab6f9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8533,7 +8532,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 53692c0020..d4af6079aa 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +212,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -643,7 +633,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1080,10 +1070,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1838,6 +1824,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6061,9 +6051,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_16_53_11_2021_575)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v49-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v50 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 86 insertions(+), 96 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.27.0 ----Next_Part(Tue_Mar__9_18_29_34_2021_806)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v50-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v51 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0dbe886f1d..15436c034b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_12_10_39_2021_432)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v52 5/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 27 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 86 insertions(+), 98 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 529876895b..99a8664026 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8554,7 +8553,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previously collected statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3335d71eba..6217ed9792 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1085,10 +1075,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1843,6 +1829,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6123,9 +6113,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 0abc41c33c..d74b5eed82 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Wed_Mar_10_17_51_37_2021_192)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v52-0006-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v56 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index b1de6d0674..0ef684d4d0 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9261,9 +9261,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a218d78bef..53d7dfda93 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7375,11 +7375,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7395,14 +7395,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7433,9 +7432,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Tue_Mar_16_10_27_55_2021_500)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v56-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v57 4/6] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 25 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 127 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- src/backend/postmaster/postmaster.c | 2 - 6 files changed, 85 insertions(+), 97 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 5c9f4af1d5..795c042a3d 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -9271,9 +9271,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 8603cf3f94..99a55d276d 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7398,11 +7398,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7418,14 +7418,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7456,9 +7455,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index f49f5c0108..45095857eb 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2217,12 +2217,13 @@ HINT: You can then restart the server after making the necessary configuration </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index db4b4e460c..90cf3072ac 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl primary server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - primary process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + primary process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -201,18 +200,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g., after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -225,48 +217,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -648,7 +638,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -1086,10 +1076,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical replication launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting in main loop of startup process for WAL to arrive, during @@ -1852,6 +1838,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </thead> <tbody> + <row> + <entry><literal>ActivityStatistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory.</entry> + </row> <row> <entry><literal>AddinShmemInit</literal></entry> <entry>Waiting to manage an extension's space allocation in shared @@ -6128,9 +6118,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index bcbb7a25fb..1fa59a2fdf 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1280,11 +1280,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 5d5802f61d..b5a37b5e0c 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -6328,8 +6328,6 @@ restore_backend_variables(BackendParameters *param, Port *port) if (postmaster_alive_fds[1] >= 0) ReserveExternalFD(); #endif - if (pgStatSock != PGINVALID_SOCKET) - ReserveExternalFD(); } -- 2.27.0 ----Next_Part(Thu_Mar_18_16_56_02_2021_947)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v57-0005-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v29 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 29 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 133 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 64614b569c..8bd8fc4d5f 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -8151,9 +8151,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 2de21903a1..7ed2b3884c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7008,11 +7008,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7028,14 +7028,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7066,9 +7065,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8129,7 +8128,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previous activity statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8142,7 +8141,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in + activity statistics. The total number of heap tuples is stored in the index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index b5d32bb720..b9b73e59f6 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2381,12 +2381,13 @@ HINT: Recovery cannot continue unless the configuration is changed and the serv </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 220b8164c3..efdcd6fda8 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -596,7 +587,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -914,7 +905,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <tbody> <row> - <entry morerows="64"><literal>LWLock</literal></entry> + <entry morerows="65"><literal>LWLock</literal></entry> <entry><literal>ShmemIndexLock</literal></entry> <entry>Waiting to find or allocate space in shared memory.</entry> </row> @@ -1197,6 +1188,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to allocate or exchange a chunk of memory or update counters during Parallel Hash plan execution.</entry> </row> + <row> + <entry><literal>activity_statistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory + during transaction end or idle time.</entry> + </row> <row> <entry morerows="9"><literal>Lock</literal></entry> <entry><literal>relation</literal></entry> @@ -1244,7 +1240,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to acquire a pin on a buffer.</entry> </row> <row> - <entry morerows="12"><literal>Activity</literal></entry> + <entry morerows="11"><literal>Activity</literal></entry> <entry><literal>ArchiverMain</literal></entry> <entry>Waiting in main loop of the archiver process.</entry> </row> @@ -1272,10 +1268,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of the statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting for WAL from a stream at recovery.</entry> @@ -4177,9 +4169,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index a9bc397165..a9289f84b0 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1289,11 +1289,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Wed_Apr__1_15_15_11_2020_923)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v29-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v30 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 29 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 133 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 64614b569c..8bd8fc4d5f 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -8151,9 +8151,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 2de21903a1..7ed2b3884c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7008,11 +7008,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7028,14 +7028,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7066,9 +7065,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8129,7 +8128,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previous activity statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8142,7 +8141,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in + activity statistics. The total number of heap tuples is stored in the index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index b5d32bb720..b9b73e59f6 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2381,12 +2381,13 @@ HINT: Recovery cannot continue unless the configuration is changed and the serv </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 220b8164c3..efdcd6fda8 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -596,7 +587,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -914,7 +905,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <tbody> <row> - <entry morerows="64"><literal>LWLock</literal></entry> + <entry morerows="65"><literal>LWLock</literal></entry> <entry><literal>ShmemIndexLock</literal></entry> <entry>Waiting to find or allocate space in shared memory.</entry> </row> @@ -1197,6 +1188,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to allocate or exchange a chunk of memory or update counters during Parallel Hash plan execution.</entry> </row> + <row> + <entry><literal>activity_statistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory + during transaction end or idle time.</entry> + </row> <row> <entry morerows="9"><literal>Lock</literal></entry> <entry><literal>relation</literal></entry> @@ -1244,7 +1240,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to acquire a pin on a buffer.</entry> </row> <row> - <entry morerows="12"><literal>Activity</literal></entry> + <entry morerows="11"><literal>Activity</literal></entry> <entry><literal>ArchiverMain</literal></entry> <entry>Waiting in main loop of the archiver process.</entry> </row> @@ -1272,10 +1268,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of the statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting for WAL from a stream at recovery.</entry> @@ -4177,9 +4169,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index a9bc397165..a9289f84b0 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1289,11 +1289,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Wed_Apr__1_17_37_23_2020_570)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v30-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v31 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 29 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 133 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 64614b569c..8bd8fc4d5f 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -8151,9 +8151,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index c4d6ed4bbc..ca737ee1fc 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7035,11 +7035,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7055,14 +7055,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7093,9 +7092,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8156,7 +8155,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previous activity statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8169,7 +8168,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in + activity statistics. The total number of heap tuples is stored in the index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index b5d32bb720..b9b73e59f6 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2381,12 +2381,13 @@ HINT: Recovery cannot continue unless the configuration is changed and the serv </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index fd8b17ef8f..95b8c3a884 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -603,7 +594,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -921,7 +912,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <tbody> <row> - <entry morerows="64"><literal>LWLock</literal></entry> + <entry morerows="65"><literal>LWLock</literal></entry> <entry><literal>ShmemIndexLock</literal></entry> <entry>Waiting to find or allocate space in shared memory.</entry> </row> @@ -1204,6 +1195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to allocate or exchange a chunk of memory or update counters during Parallel Hash plan execution.</entry> </row> + <row> + <entry><literal>activity_statistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory + during transaction end or idle time.</entry> + </row> <row> <entry morerows="9"><literal>Lock</literal></entry> <entry><literal>relation</literal></entry> @@ -1251,7 +1247,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to acquire a pin on a buffer.</entry> </row> <row> - <entry morerows="12"><literal>Activity</literal></entry> + <entry morerows="11"><literal>Activity</literal></entry> <entry><literal>ArchiverMain</literal></entry> <entry>Waiting in main loop of the archiver process.</entry> </row> @@ -1279,10 +1275,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of the statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting for WAL from a stream at recovery.</entry> @@ -4282,9 +4274,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index a9bc397165..a9289f84b0 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1289,11 +1289,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Fri_Apr__3_17_31_17_2020_104)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v31-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v32 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 29 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 133 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 64614b569c..8bd8fc4d5f 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -8151,9 +8151,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index c4d6ed4bbc..ca737ee1fc 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7035,11 +7035,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7055,14 +7055,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7093,9 +7092,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8156,7 +8155,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previous activity statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8169,7 +8168,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in + activity statistics. The total number of heap tuples is stored in the index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index b5d32bb720..b9b73e59f6 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2381,12 +2381,13 @@ HINT: Recovery cannot continue unless the configuration is changed and the serv </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index fd8b17ef8f..95b8c3a884 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -603,7 +594,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -921,7 +912,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <tbody> <row> - <entry morerows="64"><literal>LWLock</literal></entry> + <entry morerows="65"><literal>LWLock</literal></entry> <entry><literal>ShmemIndexLock</literal></entry> <entry>Waiting to find or allocate space in shared memory.</entry> </row> @@ -1204,6 +1195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to allocate or exchange a chunk of memory or update counters during Parallel Hash plan execution.</entry> </row> + <row> + <entry><literal>activity_statistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory + during transaction end or idle time.</entry> + </row> <row> <entry morerows="9"><literal>Lock</literal></entry> <entry><literal>relation</literal></entry> @@ -1251,7 +1247,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to acquire a pin on a buffer.</entry> </row> <row> - <entry morerows="12"><literal>Activity</literal></entry> + <entry morerows="11"><literal>Activity</literal></entry> <entry><literal>ArchiverMain</literal></entry> <entry>Waiting in main loop of the archiver process.</entry> </row> @@ -1279,10 +1275,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of the statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting for WAL from a stream at recovery.</entry> @@ -4282,9 +4274,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index a9bc397165..a9289f84b0 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1289,11 +1289,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Tue_Apr__7_16_38_17_2020_299)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v32-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v33 6/7] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 29 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 133 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index ce33df9e58..20ee1d5a83 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -8161,9 +8161,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a14df06292..d04b2e796c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7096,11 +7096,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -7116,14 +7116,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7154,9 +7153,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8217,7 +8216,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previous activity statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8230,7 +8229,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in + activity statistics. The total number of heap tuples is stored in the index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 52e47379cc..7c8bac2bb2 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2360,12 +2360,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 6562cc400b..6653de82e8 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (1 second unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -603,7 +594,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -921,7 +912,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <tbody> <row> - <entry morerows="64"><literal>LWLock</literal></entry> + <entry morerows="65"><literal>LWLock</literal></entry> <entry><literal>ShmemIndexLock</literal></entry> <entry>Waiting to find or allocate space in shared memory.</entry> </row> @@ -1204,6 +1195,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to allocate or exchange a chunk of memory or update counters during Parallel Hash plan execution.</entry> </row> + <row> + <entry><literal>activity_statistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory + during transaction end or idle time.</entry> + </row> <row> <entry morerows="9"><literal>Lock</literal></entry> <entry><literal>relation</literal></entry> @@ -1251,7 +1247,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to acquire a pin on a buffer.</entry> </row> <row> - <entry morerows="12"><literal>Activity</literal></entry> + <entry morerows="11"><literal>Activity</literal></entry> <entry><literal>ArchiverMain</literal></entry> <entry>Waiting in main loop of the archiver process.</entry> </row> @@ -1279,10 +1275,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of the statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalStream</literal></entry> <entry>Waiting for WAL from a stream at recovery.</entry> @@ -4282,9 +4274,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index a9bc397165..a9289f84b0 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1289,11 +1289,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Thu_Apr_30_13_22_05_2020_409)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v33-0007-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v25 7/8] Doc part of shared-memory based stats collector. @ 2020-03-19 06:11 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Kyotaro Horiguchi @ 2020-03-19 06:11 UTC (permalink / raw) --- doc/src/sgml/catalogs.sgml | 6 +- doc/src/sgml/config.sgml | 29 +++--- doc/src/sgml/high-availability.sgml | 13 +-- doc/src/sgml/monitoring.sgml | 133 +++++++++++++--------------- doc/src/sgml/ref/pg_dump.sgml | 9 +- 5 files changed, 91 insertions(+), 99 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index c6f95fa688..12c8d19ccb 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -8135,9 +8135,9 @@ SCRAM-SHA-256$<replaceable><iteration count></replaceable>:<replaceable>&l <para> <xref linkend="view-table"/> lists the system views described here. More detailed documentation of each view follows below. - There are some additional views that provide access to the results of - the statistics collector; they are described in <xref - linkend="monitoring-stats-views-table"/>. + There are some additional views that provide access to the activity + statistics; they are described in + <xref linkend="monitoring-stats-views-table"/>. </para> <para> diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 3cac340f32..8cd86beb9d 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -6944,11 +6944,11 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <title>Run-time Statistics</title> <sect2 id="runtime-config-statistics-collector"> - <title>Query and Index Statistics Collector</title> + <title>Query and Index Activity Statistics</title> <para> - These parameters control server-wide statistics collection features. - When statistics collection is enabled, the data that is produced can be + These parameters control server-wide activity statistics features. + When activity statistics is enabled, the data that is produced can be accessed via the <structname>pg_stat</structname> and <structname>pg_statio</structname> family of system views. Refer to <xref linkend="monitoring"/> for more information. @@ -6964,14 +6964,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables the collection of information on the currently - executing command of each session, along with the time when - that command began execution. This parameter is on by - default. Note that even when enabled, this information is not - visible to all users, only to superusers and the user owning - the session being reported on, so it should not represent a - security risk. - Only superusers can change this setting. + Enables activity tracking on the currently executing command of + each session, along with the time when that command began + execution. This parameter is on by default. Note that even when + enabled, this information is not visible to all users, only to + superusers and the user owning the session being reported on, so it + should not represent a security risk. Only superusers can change this + setting. </para> </listitem> </varlistentry> @@ -7002,9 +7001,9 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; </term> <listitem> <para> - Enables collection of statistics on database activity. + Enables tracking of database activity. This parameter is on by default, because the autovacuum - daemon needs the collected information. + daemon needs the activity information. Only superusers can change this setting. </para> </listitem> @@ -8022,7 +8021,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <listitem> <para> Specifies the fraction of the total number of heap tuples counted in - the previous statistics collection that can be inserted without + the previous activity statistics that can be inserted without incurring an index scan at the <command>VACUUM</command> cleanup stage. This setting currently applies to B-tree indexes only. </para> @@ -8035,7 +8034,7 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; Index statistics are considered to be stale if the number of newly inserted tuples exceeds the <varname>vacuum_cleanup_index_scale_factor</varname> fraction of the total number of heap tuples detected by the previous - statistics collection. The total number of heap tuples is stored in + activity statistics. The total number of heap tuples is stored in the index meta-page. Note that the meta-page does not include this data until <command>VACUUM</command> finds no dead tuples, so B-tree index scan at the cleanup stage can only be skipped if the second and diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index bc4d98fe03..d56afa17db 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2357,12 +2357,13 @@ LOG: database system is ready to accept read only connections </para> <para> - The statistics collector is active during recovery. All scans, reads, blocks, - index usage, etc., will be recorded normally on the standby. Replayed - actions will not duplicate their effects on primary, so replaying an - insert will not increment the Inserts column of pg_stat_user_tables. - The stats file is deleted at the start of recovery, so stats from primary - and standby will differ; this is considered a feature, not a bug. + The activity statistics is collected during recovery. All scans, reads, + blocks, index usage, etc., will be recorded normally on the + standby. Replayed actions will not duplicate their effects on primary, so + replaying an insert will not increment the Inserts column of + pg_stat_user_tables. The activity statistics is reset at the start of + recovery, so stats from primary and standby will differ; this is + considered a feature, not a bug. </para> <para> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 987580d6df..9605e0ebd4 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -22,7 +22,7 @@ <para> Several tools are available for monitoring database activity and analyzing performance. Most of this chapter is devoted to describing - <productname>PostgreSQL</productname>'s statistics collector, + <productname>PostgreSQL</productname>'s activity statistics, but one should not neglect regular Unix monitoring programs such as <command>ps</command>, <command>top</command>, <command>iostat</command>, and <command>vmstat</command>. Also, once one has identified a @@ -53,7 +53,6 @@ postgres 15554 0.0 0.0 57536 1184 ? Ss 18:02 0:00 postgres: back postgres 15555 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: checkpointer postgres 15556 0.0 0.0 57536 916 ? Ss 18:02 0:00 postgres: walwriter postgres 15557 0.0 0.0 58504 2244 ? Ss 18:02 0:00 postgres: autovacuum launcher -postgres 15558 0.0 0.0 17512 1068 ? Ss 18:02 0:00 postgres: stats collector postgres 15582 0.0 0.0 58772 3080 ? Ss 18:04 0:00 postgres: joe runbug 127.0.0.1 idle postgres 15606 0.0 0.0 58772 3052 ? Ss 18:07 0:00 postgres: tgl regression [local] SELECT waiting postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl regression [local] idle in transaction @@ -65,9 +64,8 @@ postgres 15610 0.0 0.0 58772 3056 ? Ss 18:07 0:00 postgres: tgl master server process. The command arguments shown for it are the same ones used when it was launched. The next five processes are background worker processes automatically launched by the - master process. (The <quote>stats collector</quote> process will not be present - if you have set the system not to start the statistics collector; likewise - the <quote>autovacuum launcher</quote> process can be disabled.) + master process. (The <quote>autovacuum launcher</quote> process will not + be present if you have set the system not to start it.) Each of the remaining processes is a server process handling one client connection. Each such process sets its command line display in the form @@ -130,20 +128,21 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </sect1> <sect1 id="monitoring-stats"> - <title>The Statistics Collector</title> + <title>The Activity Statistics</title> <indexterm zone="monitoring-stats"> <primary>statistics</primary> </indexterm> <para> - <productname>PostgreSQL</productname>'s <firstterm>statistics collector</firstterm> - is a subsystem that supports collection and reporting of information about - server activity. Presently, the collector can count accesses to tables - and indexes in both disk-block and individual-row terms. It also tracks - the total number of rows in each table, and information about vacuum and - analyze actions for each table. It can also count calls to user-defined - functions and the total time spent in each one. + <productname>PostgreSQL</productname>'s <firstterm>activity + statistics</firstterm> is a subsystem that supports tracking and reporting + of information about server activity. Presently, the activity statistics + tracks the count of accesses to tables and indexes in both disk-block and + individual-row terms. It also tracks the total number of rows in each + table, and information about vacuum and analyze actions for each table. It + can also track calls to user-defined functions and the total time spent in + each one. </para> <para> @@ -151,15 +150,15 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser information about exactly what is going on in the system right now, such as the exact command currently being executed by other server processes, and which other connections exist in the system. This facility is independent - of the collector process. + of the activity statistics. </para> <sect2 id="monitoring-stats-setup"> - <title>Statistics Collection Configuration</title> + <title>Activity Statistics Configuration</title> <para> - Since collection of statistics adds some overhead to query execution, - the system can be configured to collect or not collect information. + Since tracking for the activity statistics adds some overhead to query + execution, the system can be configured to track or not track activity. This is controlled by configuration parameters that are normally set in <filename>postgresql.conf</filename>. (See <xref linkend="runtime-config"/> for details about setting configuration parameters.) @@ -172,7 +171,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <para> The parameter <xref linkend="guc-track-counts"/> controls whether - statistics are collected about table and index accesses. + to track activity about table and index accesses. </para> <para> @@ -196,18 +195,12 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </para> <para> - The statistics collector transmits the collected information to other - <productname>PostgreSQL</productname> processes through temporary files. - These files are stored in the directory named by the - <xref linkend="guc-stats-temp-directory"/> parameter, - <filename>pg_stat_tmp</filename> by default. - For better performance, <varname>stats_temp_directory</varname> can be - pointed at a RAM-based file system, decreasing physical I/O requirements. - When the server shuts down cleanly, a permanent copy of the statistics - data is stored in the <filename>pg_stat</filename> subdirectory, so that - statistics can be retained across server restarts. When recovery is - performed at server start (e.g. after immediate shutdown, server crash, - and point-in-time recovery), all statistics counters are reset. + The activity statistics is placed on shared memory. When the server shuts + down cleanly, a permanent copy of the statistics data is stored in + the <filename>pg_stat</filename> subdirectory, so that statistics can be + retained across server restarts. When recovery is performed at server + start (e.g. after immediate shutdown, server crash, and point-in-time + recovery), all statistics counters are reset. </para> </sect2> @@ -220,48 +213,46 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser linkend="monitoring-stats-dynamic-views-table"/>, are available to show the current state of the system. There are also several other views, listed in <xref - linkend="monitoring-stats-views-table"/>, available to show the results - of statistics collection. Alternatively, one can - build custom views using the underlying statistics functions, as discussed - in <xref linkend="monitoring-stats-functions"/>. + linkend="monitoring-stats-views-table"/>, available to show the activity + statistics. Alternatively, one can build custom views using the underlying + statistics functions, as discussed in + <xref linkend="monitoring-stats-functions"/>. </para> <para> - When using the statistics to monitor collected data, it is important - to realize that the information does not update instantaneously. - Each individual server process transmits new statistical counts to - the collector just before going idle; so a query or transaction still in - progress does not affect the displayed totals. Also, the collector itself - emits a new report at most once per <varname>PGSTAT_STAT_INTERVAL</varname> - milliseconds (500 ms unless altered while building the server). So the - displayed information lags behind actual activity. However, current-query - information collected by <varname>track_activities</varname> is - always up-to-date. + When using the activity statistics, it is important to realize that the + information does not update instantaneously. Each individual server writes + out new statistical counts just before going idle, not frequent than once + per <varname>PGSTAT_STAT_INTERVAL</varname> milliseconds (500 ms unless + altered while building the server); so a query or transaction still in + progress does not affect the displayed totals. However, current-query + information tracked by <varname>track_activities</varname> is always + up-to-date. </para> <para> Another important point is that when a server process is asked to display - any of these statistics, it first fetches the most recent report emitted by - the collector process and then continues to use this snapshot for all - statistical views and functions until the end of its current transaction. - So the statistics will show static information as long as you continue the - current transaction. Similarly, information about the current queries of - all sessions is collected when any such information is first requested - within a transaction, and the same information will be displayed throughout - the transaction. - This is a feature, not a bug, because it allows you to perform several - queries on the statistics and correlate the results without worrying that - the numbers are changing underneath you. But if you want to see new - results with each query, be sure to do the queries outside any transaction - block. Alternatively, you can invoke + any of these statistics, it first reads the current statistics and then + continues to use this snapshot for all statistical views and functions + until the end of its current transaction. So the statistics will show + static information as long as you continue the current transaction. + Similarly, information about the current queries of all sessions is tracked + when any such information is first requested within a transaction, and the + same information will be displayed throughout the transaction. This is a + feature, not a bug, because it allows you to perform several queries on the + statistics and correlate the results without worrying that the numbers are + changing underneath you. But if you want to see new results with each + query, be sure to do the queries outside any transaction block. + Alternatively, you can invoke <function>pg_stat_clear_snapshot</function>(), which will discard the current transaction's statistics snapshot (if any). The next use of statistical information will cause a new snapshot to be fetched. </para> - + <para> - A transaction can also see its own statistics (as yet untransmitted to the - collector) in the views <structname>pg_stat_xact_all_tables</structname>, + A transaction can also see its own statistics (as yet unwritten to the + server-wide activity statistics) in the + views <structname>pg_stat_xact_all_tables</structname>, <structname>pg_stat_xact_sys_tables</structname>, <structname>pg_stat_xact_user_tables</structname>, and <structname>pg_stat_xact_user_functions</structname>. These numbers do not act as @@ -596,7 +587,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser kernel's I/O cache, and might therefore still be fetched without requiring a physical read. Users interested in obtaining more detailed information on <productname>PostgreSQL</productname> I/O behavior are - advised to use the <productname>PostgreSQL</productname> statistics collector + advised to use the <productname>PostgreSQL</productname> activity statistics in combination with operating system utilities that allow insight into the kernel's handling of I/O. </para> @@ -914,7 +905,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <tbody> <row> - <entry morerows="64"><literal>LWLock</literal></entry> + <entry morerows="65"><literal>LWLock</literal></entry> <entry><literal>ShmemIndexLock</literal></entry> <entry>Waiting to find or allocate space in shared memory.</entry> </row> @@ -1197,6 +1188,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to allocate or exchange a chunk of memory or update counters during Parallel Hash plan execution.</entry> </row> + <row> + <entry><literal>activity_statistics</literal></entry> + <entry>Waiting to write out activity statistics to shared memory + during transaction end or idle time.</entry> + </row> <row> <entry morerows="9"><literal>Lock</literal></entry> <entry><literal>relation</literal></entry> @@ -1244,7 +1240,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry>Waiting to acquire a pin on a buffer.</entry> </row> <row> - <entry morerows="13"><literal>Activity</literal></entry> + <entry morerows="12"><literal>Activity</literal></entry> <entry><literal>ArchiverMain</literal></entry> <entry>Waiting in main loop of the archiver process.</entry> </row> @@ -1272,10 +1268,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser <entry><literal>LogicalLauncherMain</literal></entry> <entry>Waiting in main loop of logical launcher process.</entry> </row> - <row> - <entry><literal>PgStatMain</literal></entry> - <entry>Waiting in main loop of the statistics collector process.</entry> - </row> <row> <entry><literal>RecoveryWalAll</literal></entry> <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry> @@ -4156,9 +4148,10 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid, <entry><literal>performing final cleanup</literal></entry> <entry> <command>VACUUM</command> is performing final cleanup. During this phase, - <command>VACUUM</command> will vacuum the free space map, update statistics - in <literal>pg_class</literal>, and report statistics to the statistics - collector. When this phase is completed, <command>VACUUM</command> will end. + <command>VACUUM</command> will vacuum the free space map, update + statistics in <literal>pg_class</literal>, and system-wide activity + statistics. When this phase is completed, <command>VACUUM</command> + will end. </entry> </row> </tbody> diff --git a/doc/src/sgml/ref/pg_dump.sgml b/doc/src/sgml/ref/pg_dump.sgml index 13bd320b31..52c61d222a 100644 --- a/doc/src/sgml/ref/pg_dump.sgml +++ b/doc/src/sgml/ref/pg_dump.sgml @@ -1259,11 +1259,10 @@ PostgreSQL documentation </para> <para> - The database activity of <application>pg_dump</application> is - normally collected by the statistics collector. If this is - undesirable, you can set parameter <varname>track_counts</varname> - to false via <envar>PGOPTIONS</envar> or the <literal>ALTER - USER</literal> command. + The database activity of <application>pg_dump</application> is normally + collected. If this is undesirable, you can set + parameter <varname>track_counts</varname> to false + via <envar>PGOPTIONS</envar> or the <literal>ALTER USER</literal> command. </para> </refsect1> -- 2.18.2 ----Next_Part(Thu_Mar_19_20_30_04_2020_284)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v25-0008-Remove-the-GUC-stats_temp_directory.patch" ^ permalink raw reply [nested|flat] 228+ messages in thread
* [PATCH v4 3/3] have psql \d+ show the constraint name @ 2023-02-24 11:02 Alvaro Herrera <[email protected]> 0 siblings, 0 replies; 228+ messages in thread From: Alvaro Herrera @ 2023-02-24 11:02 UTC (permalink / raw) --- .../postgres_fdw/expected/postgres_fdw.out | 20 +- contrib/test_decoding/expected/ddl.out | 50 +- src/bin/psql/describe.c | 29 +- src/test/regress/expected/alter_table.out | 74 +-- src/test/regress/expected/collate.out | 8 +- src/test/regress/expected/compression.out | 104 ++-- src/test/regress/expected/compression_1.out | 72 +-- src/test/regress/expected/copy2.out | 8 +- src/test/regress/expected/create_table.out | 142 ++--- .../regress/expected/create_table_like.out | 88 +-- src/test/regress/expected/create_view.out | 348 +++++------ src/test/regress/expected/domain.out | 16 +- src/test/regress/expected/expressions.out | 36 +- src/test/regress/expected/foreign_data.out | 580 +++++++++--------- src/test/regress/expected/generated.out | 12 +- src/test/regress/expected/identity.out | 16 +- src/test/regress/expected/inherit.out | 138 ++--- src/test/regress/expected/insert.out | 118 ++-- src/test/regress/expected/limit.out | 32 +- src/test/regress/expected/matview.out | 90 +-- src/test/regress/expected/polymorphism.out | 14 +- src/test/regress/expected/psql.out | 40 +- src/test/regress/expected/publication.out | 88 +-- .../regress/expected/replica_identity.out | 30 +- src/test/regress/expected/rowsecurity.out | 16 +- src/test/regress/expected/rules.out | 78 +-- src/test/regress/expected/stats_ext.out | 10 +- src/test/regress/expected/tablesample.out | 16 +- src/test/regress/expected/tablespace.out | 16 +- src/test/regress/expected/triggers.out | 18 +- src/test/regress/expected/updatable_views.out | 34 +- src/test/regress/expected/update.out | 16 +- src/test/regress/expected/with.out | 8 +- 33 files changed, 1191 insertions(+), 1174 deletions(-) diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index 04a3ef450c..518658fe5c 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -6545,11 +6545,11 @@ CREATE FOREIGN TABLE foreign_tbl (a int, b int) CREATE VIEW rw_view AS SELECT * FROM foreign_tbl WHERE a < b WITH CHECK OPTION; \d+ rw_view - View "public.rw_view" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | - b | integer | | | | plain | + View "public.rw_view" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | + b | integer | | | | plain | View definition: SELECT a, b @@ -6662,11 +6662,11 @@ ALTER TABLE parent_tbl ATTACH PARTITION foreign_tbl FOR VALUES FROM (0) TO (100) CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < b WITH CHECK OPTION; \d+ rw_view - View "public.rw_view" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | - b | integer | | | | plain | + View "public.rw_view" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | + b | integer | | | | plain | View definition: SELECT a, b diff --git a/contrib/test_decoding/expected/ddl.out b/contrib/test_decoding/expected/ddl.out index 9a28b5ddc5..df28ceef7f 100644 --- a/contrib/test_decoding/expected/ddl.out +++ b/contrib/test_decoding/expected/ddl.out @@ -484,12 +484,12 @@ CREATE TABLE replication_metadata ( WITH (user_catalog_table = true) ; \d+ replication_metadata - Table "public.replication_metadata" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------+---------+-----------+----------+--------------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('replication_metadata_id_seq'::regclass) | plain | | - relation | name | | not null | | plain | | - options | text[] | | | | extended | | + Table "public.replication_metadata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------+---------+-----------+----------------------------------------+--------------------------------------------------+----------+--------------+------------- + id | integer | | replication_metadata_id_not_null | nextval('replication_metadata_id_seq'::regclass) | plain | | + relation | name | | replication_metadata_relation_not_null | | plain | | + options | text[] | | | | extended | | Indexes: "replication_metadata_pkey" PRIMARY KEY, btree (id) Options: user_catalog_table=true @@ -498,12 +498,12 @@ INSERT INTO replication_metadata(relation, options) VALUES ('foo', ARRAY['a', 'b']); ALTER TABLE replication_metadata RESET (user_catalog_table); \d+ replication_metadata - Table "public.replication_metadata" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------+---------+-----------+----------+--------------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('replication_metadata_id_seq'::regclass) | plain | | - relation | name | | not null | | plain | | - options | text[] | | | | extended | | + Table "public.replication_metadata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------+---------+-----------+----------------------------------------+--------------------------------------------------+----------+--------------+------------- + id | integer | | replication_metadata_id_not_null | nextval('replication_metadata_id_seq'::regclass) | plain | | + relation | name | | replication_metadata_relation_not_null | | plain | | + options | text[] | | | | extended | | Indexes: "replication_metadata_pkey" PRIMARY KEY, btree (id) @@ -511,12 +511,12 @@ INSERT INTO replication_metadata(relation, options) VALUES ('bar', ARRAY['a', 'b']); ALTER TABLE replication_metadata SET (user_catalog_table = true); \d+ replication_metadata - Table "public.replication_metadata" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------+---------+-----------+----------+--------------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('replication_metadata_id_seq'::regclass) | plain | | - relation | name | | not null | | plain | | - options | text[] | | | | extended | | + Table "public.replication_metadata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------+---------+-----------+----------------------------------------+--------------------------------------------------+----------+--------------+------------- + id | integer | | replication_metadata_id_not_null | nextval('replication_metadata_id_seq'::regclass) | plain | | + relation | name | | replication_metadata_relation_not_null | | plain | | + options | text[] | | | | extended | | Indexes: "replication_metadata_pkey" PRIMARY KEY, btree (id) Options: user_catalog_table=true @@ -529,13 +529,13 @@ ALTER TABLE replication_metadata ALTER COLUMN rewritemeornot TYPE text; ERROR: cannot rewrite table "replication_metadata" used as a catalog table ALTER TABLE replication_metadata SET (user_catalog_table = false); \d+ replication_metadata - Table "public.replication_metadata" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------------+---------+-----------+----------+--------------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('replication_metadata_id_seq'::regclass) | plain | | - relation | name | | not null | | plain | | - options | text[] | | | | extended | | - rewritemeornot | integer | | | | plain | | + Table "public.replication_metadata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------------+---------+-----------+----------------------------------------+--------------------------------------------------+----------+--------------+------------- + id | integer | | replication_metadata_id_not_null | nextval('replication_metadata_id_seq'::regclass) | plain | | + relation | name | | replication_metadata_relation_not_null | | plain | | + options | text[] | | | | extended | | + rewritemeornot | integer | | | | plain | | Indexes: "replication_metadata_pkey" PRIMARY KEY, btree (id) Options: user_catalog_table=false diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c index c8a0bb7b3a..63e9037b20 100644 --- a/src/bin/psql/describe.c +++ b/src/bin/psql/describe.c @@ -1853,9 +1853,20 @@ describeOneTableDetails(const char *schemaname, appendPQExpBufferStr(&buf, ",\n (SELECT pg_catalog.pg_get_expr(d.adbin, d.adrelid, true)" "\n FROM pg_catalog.pg_attrdef d" - "\n WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)" - ",\n a.attnotnull"); + "\n WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)"); attrdef_col = cols++; + if (verbose && pset.sversion >= 160000) + { + appendPQExpBuffer(&buf, + ",\n (SELECT CASE when contype = 'n' THEN conname ELSE '(primary key)' END" + "\n FROM pg_catalog.pg_constraint co" + "\n WHERE co.conrelid = '%s' AND co.contype IN ('n', 'p') " + "\n AND co.conkey @> array[attnum]" + "\n ORDER BY contype <> 'n' LIMIT 1) AS attnotnull", + oid); + } + else + appendPQExpBufferStr(&buf, ",\n a.attnotnull"); attnotnull_col = cols++; appendPQExpBufferStr(&buf, ",\n (SELECT c.collname FROM pg_catalog.pg_collation c, pg_catalog.pg_type t\n" " WHERE c.oid = a.attcollation AND t.oid = a.atttypid AND a.attcollation <> t.typcollation) AS attcollation"); @@ -2019,7 +2030,8 @@ describeOneTableDetails(const char *schemaname, if (show_column_details) { headers[cols++] = gettext_noop("Collation"); - headers[cols++] = gettext_noop("Nullable"); + headers[cols++] = verbose ? gettext_noop("NOT NULL Constraint") : + gettext_noop("Nullable"); headers[cols++] = gettext_noop("Default"); } if (isindexkey_col >= 0) @@ -2064,9 +2076,14 @@ describeOneTableDetails(const char *schemaname, printTableAddCell(&cont, PQgetvalue(res, i, attcoll_col), false, false); - printTableAddCell(&cont, - strcmp(PQgetvalue(res, i, attnotnull_col), "t") == 0 ? "not null" : "", - false, false); + if (verbose) + printTableAddCell(&cont, + PQgetvalue(res, i, attnotnull_col), + false, false); + else + printTableAddCell(&cont, + strcmp(PQgetvalue(res, i, attnotnull_col), "t") == 0 ? "not null" : "", + false, false); identity = PQgetvalue(res, i, attidentity_col); generated = PQgetvalue(res, i, attgenerated_col); diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out index d19349b301..fac453c01b 100644 --- a/src/test/regress/expected/alter_table.out +++ b/src/test/regress/expected/alter_table.out @@ -2282,12 +2282,12 @@ ERROR: column data type integer can only have storage PLAIN create index test_storage_idx on test_storage (b, a); alter table test_storage alter column a set storage external; \d+ test_storage - Table "public.test_storage" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+-------------------+----------+--------------+------------- - a | text | | | | external | | - c | text | | | | plain | | - b | integer | | | random()::integer | plain | | + Table "public.test_storage" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+-------------------+----------+--------------+------------- + a | text | | | | external | | + c | text | | | | plain | | + b | integer | | | random()::integer | plain | | Indexes: "test_storage_idx" btree (b, a) @@ -2492,23 +2492,23 @@ insert into at_base_table values (23, 'skidoo'); create view at_view_1 as select * from at_base_table bt; create view at_view_2 as select *, to_json(v1) as j from at_view_1 v1; \d+ at_view_1 - View "public.at_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - id | integer | | | | plain | - stuff | text | | | | extended | + View "public.at_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + id | integer | | | | plain | + stuff | text | | | | extended | View definition: SELECT id, stuff FROM at_base_table bt; \d+ at_view_2 - View "public.at_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - id | integer | | | | plain | - stuff | text | | | | extended | - j | json | | | | extended | + View "public.at_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + id | integer | | | | plain | + stuff | text | | | | extended | + j | json | | | | extended | View definition: SELECT id, stuff, @@ -2530,12 +2530,12 @@ select * from at_view_2; create or replace view at_view_1 as select *, 2+2 as more from at_base_table bt; \d+ at_view_1 - View "public.at_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - id | integer | | | | plain | - stuff | text | | | | extended | - more | integer | | | | plain | + View "public.at_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + id | integer | | | | plain | + stuff | text | | | | extended | + more | integer | | | | plain | View definition: SELECT id, stuff, @@ -2543,12 +2543,12 @@ View definition: FROM at_base_table bt; \d+ at_view_2 - View "public.at_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - id | integer | | | | plain | - stuff | text | | | | extended | - j | json | | | | extended | + View "public.at_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + id | integer | | | | plain | + stuff | text | | | | extended | + j | json | | | | extended | View definition: SELECT id, stuff, @@ -4275,10 +4275,10 @@ DROP TABLE part_rpd; -- works fine ALTER TABLE range_parted2 DETACH PARTITION part_rp CONCURRENTLY; \d+ range_parted2 - Partitioned table "public.range_parted2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | + Partitioned table "public.range_parted2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | Partition key: RANGE (a) Number of partitions: 0 @@ -4619,10 +4619,10 @@ create publication pub1 for table alter1.t1, tables in schema alter2; reset client_min_messages; alter table alter1.t1 set schema alter2; \d+ alter2.t1 - Table "alter2.t1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | + Table "alter2.t1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | Publications: "pub1" diff --git a/src/test/regress/expected/collate.out b/src/test/regress/expected/collate.out index 0649564485..a37814570e 100644 --- a/src/test/regress/expected/collate.out +++ b/src/test/regress/expected/collate.out @@ -693,10 +693,10 @@ CREATE VIEW collate_on_int AS SELECT c1+1 AS c1p FROM (SELECT ('4' COLLATE "C")::INT AS c1) ss; \d+ collate_on_int - View "collate_tests.collate_on_int" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - c1p | integer | | | | plain | + View "collate_tests.collate_on_int" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + c1p | integer | | | | plain | View definition: SELECT c1 + 1 AS c1p FROM ( SELECT 4 AS c1) ss; diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out index e06ac93a36..6dedb4a9c6 100644 --- a/src/test/regress/expected/compression.out +++ b/src/test/regress/expected/compression.out @@ -6,20 +6,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz); CREATE INDEX idx ON cmdata(f1); INSERT INTO cmdata VALUES(repeat('1234567890', 1000)); \d+ cmdata - Table "public.cmdata" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | pglz | | + Table "public.cmdata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | pglz | | Indexes: "idx" btree (f1) CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4); INSERT INTO cmdata1 VALUES(repeat('1234567890', 1004)); \d+ cmdata1 - Table "public.cmdata1" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | lz4 | | + Table "public.cmdata1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | lz4 | | -- verify stored compression method in the data SELECT pg_column_compression(f1) FROM cmdata; @@ -50,10 +50,10 @@ SELECT SUBSTR(f1, 2000, 50) FROM cmdata1; -- copy with table creation SELECT * INTO cmmove1 FROM cmdata; \d+ cmmove1 - Table "public.cmmove1" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | | | + Table "public.cmmove1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | | | SELECT pg_column_compression(f1) FROM cmmove1; pg_column_compression @@ -75,10 +75,10 @@ SELECT pg_column_compression(f1) FROM cmmove3; -- test LIKE INCLUDING COMPRESSION CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION); \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | lz4 | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | lz4 | | DROP TABLE cmdata2; -- try setting compression for incompressible data type @@ -136,41 +136,41 @@ DROP TABLE cmdata2; --test column type update varlena/non-varlena CREATE TABLE cmdata2 (f1 int); \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+---------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | integer | | | | plain | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | integer | | | | plain | | | ALTER TABLE cmdata2 ALTER COLUMN f1 TYPE varchar; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | character varying | | | | extended | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | character varying | | | | extended | | | ALTER TABLE cmdata2 ALTER COLUMN f1 TYPE int USING f1::integer; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+---------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | integer | | | | plain | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | integer | | | | plain | | | --changing column storage should not impact the compression method --but the data should not be compressed ALTER TABLE cmdata2 ALTER COLUMN f1 TYPE varchar; ALTER TABLE cmdata2 ALTER COLUMN f1 SET COMPRESSION pglz; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | character varying | | | | extended | pglz | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | character varying | | | | extended | pglz | | ALTER TABLE cmdata2 ALTER COLUMN f1 SET STORAGE plain; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | character varying | | | | plain | pglz | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | character varying | | | | plain | pglz | | INSERT INTO cmdata2 VALUES (repeat('123456789', 800)); SELECT pg_column_compression(f1) FROM cmdata2; @@ -182,10 +182,10 @@ SELECT pg_column_compression(f1) FROM cmdata2; -- test compression with materialized view CREATE MATERIALIZED VIEW compressmv(x) AS SELECT * FROM cmdata1; \d+ compressmv - Materialized view "public.compressmv" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - x | text | | | | extended | | | + Materialized view "public.compressmv" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + x | text | | | | extended | | | View definition: SELECT f1 AS x FROM cmdata1; @@ -245,10 +245,10 @@ SET default_toast_compression = 'pglz'; ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4; INSERT INTO cmdata VALUES (repeat('123456789', 4004)); \d+ cmdata - Table "public.cmdata" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | lz4 | | + Table "public.cmdata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | lz4 | | Indexes: "idx" btree (f1) @@ -261,18 +261,18 @@ SELECT pg_column_compression(f1) FROM cmdata; ALTER TABLE cmdata2 ALTER COLUMN f1 SET COMPRESSION default; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | character varying | | | | plain | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | character varying | | | | plain | | | -- test alter compression method for materialized views ALTER MATERIALIZED VIEW compressmv ALTER COLUMN x SET COMPRESSION lz4; \d+ compressmv - Materialized view "public.compressmv" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - x | text | | | | extended | lz4 | | + Materialized view "public.compressmv" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + x | text | | | | extended | lz4 | | View definition: SELECT f1 AS x FROM cmdata1; diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out index c0a47646eb..69555f6218 100644 --- a/src/test/regress/expected/compression_1.out +++ b/src/test/regress/expected/compression_1.out @@ -6,10 +6,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz); CREATE INDEX idx ON cmdata(f1); INSERT INTO cmdata VALUES(repeat('1234567890', 1000)); \d+ cmdata - Table "public.cmdata" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | pglz | | + Table "public.cmdata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | pglz | | Indexes: "idx" btree (f1) @@ -46,10 +46,10 @@ LINE 1: SELECT SUBSTR(f1, 2000, 50) FROM cmdata1; -- copy with table creation SELECT * INTO cmmove1 FROM cmdata; \d+ cmmove1 - Table "public.cmmove1" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | | | + Table "public.cmmove1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | | | SELECT pg_column_compression(f1) FROM cmmove1; pg_column_compression @@ -133,41 +133,41 @@ DROP TABLE cmdata2; --test column type update varlena/non-varlena CREATE TABLE cmdata2 (f1 int); \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+---------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | integer | | | | plain | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | integer | | | | plain | | | ALTER TABLE cmdata2 ALTER COLUMN f1 TYPE varchar; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | character varying | | | | extended | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | character varying | | | | extended | | | ALTER TABLE cmdata2 ALTER COLUMN f1 TYPE int USING f1::integer; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+---------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | integer | | | | plain | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | integer | | | | plain | | | --changing column storage should not impact the compression method --but the data should not be compressed ALTER TABLE cmdata2 ALTER COLUMN f1 TYPE varchar; ALTER TABLE cmdata2 ALTER COLUMN f1 SET COMPRESSION pglz; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | character varying | | | | extended | pglz | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | character varying | | | | extended | pglz | | ALTER TABLE cmdata2 ALTER COLUMN f1 SET STORAGE plain; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | character varying | | | | plain | pglz | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | character varying | | | | plain | pglz | | INSERT INTO cmdata2 VALUES (repeat('123456789', 800)); SELECT pg_column_compression(f1) FROM cmdata2; @@ -240,10 +240,10 @@ ERROR: compression method lz4 not supported DETAIL: This functionality requires the server to be built with lz4 support. INSERT INTO cmdata VALUES (repeat('123456789', 4004)); \d+ cmdata - Table "public.cmdata" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+------+-----------+----------+---------+----------+-------------+--------------+------------- - f1 | text | | | | extended | pglz | | + Table "public.cmdata" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+------+-----------+---------------------+---------+----------+-------------+--------------+------------- + f1 | text | | | | extended | pglz | | Indexes: "idx" btree (f1) @@ -256,10 +256,10 @@ SELECT pg_column_compression(f1) FROM cmdata; ALTER TABLE cmdata2 ALTER COLUMN f1 SET COMPRESSION default; \d+ cmdata2 - Table "public.cmdata2" - Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description ---------+-------------------+-----------+----------+---------+---------+-------------+--------------+------------- - f1 | character varying | | | | plain | | | + Table "public.cmdata2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Compression | Stats target | Description +--------+-------------------+-----------+---------------------+---------+---------+-------------+--------------+------------- + f1 | character varying | | | | plain | | | -- test alter compression method for materialized views ALTER MATERIALIZED VIEW compressmv ALTER COLUMN x SET COMPRESSION lz4; diff --git a/src/test/regress/expected/copy2.out b/src/test/regress/expected/copy2.out index 090ef6c7a8..ae4d4e995d 100644 --- a/src/test/regress/expected/copy2.out +++ b/src/test/regress/expected/copy2.out @@ -530,10 +530,10 @@ begin end $$ language plpgsql immutable; alter table check_con_tbl add check (check_con_function(check_con_tbl.*)); \d+ check_con_tbl - Table "public.check_con_tbl" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - f1 | integer | | | | plain | | + Table "public.check_con_tbl" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + f1 | integer | | | | plain | | Check constraints: "check_con_tbl_check" CHECK (check_con_function(check_con_tbl.*)) diff --git a/src/test/regress/expected/create_table.out b/src/test/regress/expected/create_table.out index 32102204a1..5f21714b13 100644 --- a/src/test/regress/expected/create_table.out +++ b/src/test/regress/expected/create_table.out @@ -293,11 +293,11 @@ Partition key: RANGE (a oid_ops, plusone(b), c, d COLLATE "C") Number of partitions: 0 \d+ partitioned2 - Partitioned table "public.partitioned2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | integer | | | | plain | | - b | text | | | | extended | | + Partitioned table "public.partitioned2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | integer | | | | plain | | + b | text | | | | extended | | Partition key: RANGE (((a + 1)), substr(b, 1, 5)) Number of partitions: 0 @@ -306,11 +306,11 @@ ERROR: no partition of relation "partitioned2" found for row DETAIL: Partition key of the failing row contains ((a + 1), substr(b, 1, 5)) = (2, hello). CREATE TABLE part2_1 PARTITION OF partitioned2 FOR VALUES FROM (-1, 'aaaaa') TO (100, 'ccccc'); \d+ part2_1 - Table "public.part2_1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | integer | | | | plain | | - b | text | | | | extended | | + Table "public.part2_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | integer | | | | plain | | + b | text | | | | extended | | Partition of: partitioned2 FOR VALUES FROM ('-1', 'aaaaa') TO (100, 'ccccc') Partition constraint: (((a + 1) IS NOT NULL) AND (substr(b, 1, 5) IS NOT NULL) AND (((a + 1) > '-1'::integer) OR (((a + 1) = '-1'::integer) AND (substr(b, 1, 5) >= 'aaaaa'::text))) AND (((a + 1) < 100) OR (((a + 1) = 100) AND (substr(b, 1, 5) < 'ccccc'::text)))) @@ -347,11 +347,11 @@ select * from partitioned where partitioned = '(1,2)'::partitioned; (2 rows) \d+ partitioned1 - Table "public.partitioned1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | - b | integer | | | | plain | | + Table "public.partitioned1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | + b | integer | | | | plain | | Partition of: partitioned FOR VALUES IN ('(1,2)') Partition constraint: (((partitioned1.*)::partitioned IS DISTINCT FROM NULL) AND ((partitioned1.*)::partitioned = '(1,2)'::partitioned)) @@ -404,10 +404,10 @@ CREATE TABLE part_p2 PARTITION OF list_parted FOR VALUES IN (2); CREATE TABLE part_p3 PARTITION OF list_parted FOR VALUES IN ((2+1)); CREATE TABLE part_null PARTITION OF list_parted FOR VALUES IN (null); \d+ list_parted - Partitioned table "public.list_parted" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | + Partitioned table "public.list_parted" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | Partition key: LIST (a) Partitions: part_null FOR VALUES IN (NULL), part_p1 FOR VALUES IN (1), @@ -855,21 +855,21 @@ create table test_part_coll_cast2 partition of test_part_coll_posix for values f drop table test_part_coll_posix; -- Partition bound in describe output \d+ part_b - Table "public.part_b" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | not null | 1 | plain | | + Table "public.part_b" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | part_b_b_not_null | 1 | plain | | Partition of: parted FOR VALUES IN ('b') Partition constraint: ((a IS NOT NULL) AND (a = 'b'::text)) -- Both partition bound and partition key in describe output \d+ part_c - Partitioned table "public.part_c" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | not null | 0 | plain | | + Partitioned table "public.part_c" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | part_c_b_not_null | 0 | plain | | Partition of: parted FOR VALUES IN ('c') Partition constraint: ((a IS NOT NULL) AND (a = 'c'::text)) Partition key: RANGE (b) @@ -877,11 +877,11 @@ Partitions: part_c_1_10 FOR VALUES FROM (1) TO (10) -- a level-2 partition's constraint will include the parent's expressions \d+ part_c_1_10 - Table "public.part_c_1_10" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | not null | 0 | plain | | + Table "public.part_c_1_10" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | part_c_b_not_null | 0 | plain | | Partition of: part_c FOR VALUES FROM (1) TO (10) Partition constraint: ((a IS NOT NULL) AND (a = 'c'::text) AND (b IS NOT NULL) AND (b >= 1) AND (b < 10)) @@ -910,46 +910,46 @@ Number of partitions: 4 (Use \d+ to list them.) CREATE TABLE range_parted4 (a int, b int, c int) PARTITION BY RANGE (abs(a), abs(b), c); CREATE TABLE unbounded_range_part PARTITION OF range_parted4 FOR VALUES FROM (MINVALUE, MINVALUE, MINVALUE) TO (MAXVALUE, MAXVALUE, MAXVALUE); \d+ unbounded_range_part - Table "public.unbounded_range_part" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | - b | integer | | | | plain | | - c | integer | | | | plain | | + Table "public.unbounded_range_part" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | + b | integer | | | | plain | | + c | integer | | | | plain | | Partition of: range_parted4 FOR VALUES FROM (MINVALUE, MINVALUE, MINVALUE) TO (MAXVALUE, MAXVALUE, MAXVALUE) Partition constraint: ((abs(a) IS NOT NULL) AND (abs(b) IS NOT NULL) AND (c IS NOT NULL)) DROP TABLE unbounded_range_part; CREATE TABLE range_parted4_1 PARTITION OF range_parted4 FOR VALUES FROM (MINVALUE, MINVALUE, MINVALUE) TO (1, MAXVALUE, MAXVALUE); \d+ range_parted4_1 - Table "public.range_parted4_1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | - b | integer | | | | plain | | - c | integer | | | | plain | | + Table "public.range_parted4_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | + b | integer | | | | plain | | + c | integer | | | | plain | | Partition of: range_parted4 FOR VALUES FROM (MINVALUE, MINVALUE, MINVALUE) TO (1, MAXVALUE, MAXVALUE) Partition constraint: ((abs(a) IS NOT NULL) AND (abs(b) IS NOT NULL) AND (c IS NOT NULL) AND (abs(a) <= 1)) CREATE TABLE range_parted4_2 PARTITION OF range_parted4 FOR VALUES FROM (3, 4, 5) TO (6, 7, MAXVALUE); \d+ range_parted4_2 - Table "public.range_parted4_2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | - b | integer | | | | plain | | - c | integer | | | | plain | | + Table "public.range_parted4_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | + b | integer | | | | plain | | + c | integer | | | | plain | | Partition of: range_parted4 FOR VALUES FROM (3, 4, 5) TO (6, 7, MAXVALUE) Partition constraint: ((abs(a) IS NOT NULL) AND (abs(b) IS NOT NULL) AND (c IS NOT NULL) AND ((abs(a) > 3) OR ((abs(a) = 3) AND (abs(b) > 4)) OR ((abs(a) = 3) AND (abs(b) = 4) AND (c >= 5))) AND ((abs(a) < 6) OR ((abs(a) = 6) AND (abs(b) <= 7)))) CREATE TABLE range_parted4_3 PARTITION OF range_parted4 FOR VALUES FROM (6, 8, MINVALUE) TO (9, MAXVALUE, MAXVALUE); \d+ range_parted4_3 - Table "public.range_parted4_3" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | - b | integer | | | | plain | | - c | integer | | | | plain | | + Table "public.range_parted4_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | + b | integer | | | | plain | | + c | integer | | | | plain | | Partition of: range_parted4 FOR VALUES FROM (6, 8, MINVALUE) TO (9, MAXVALUE, MAXVALUE) Partition constraint: ((abs(a) IS NOT NULL) AND (abs(b) IS NOT NULL) AND (c IS NOT NULL) AND ((abs(a) > 6) OR ((abs(a) = 6) AND (abs(b) >= 8))) AND (abs(a) <= 9)) @@ -981,11 +981,11 @@ SELECT obj_description('parted_col_comment'::regclass); (1 row) \d+ parted_col_comment - Partitioned table "public.parted_col_comment" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+--------------- - a | integer | | | | plain | | Partition key - b | text | | | | extended | | + Partitioned table "public.parted_col_comment" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+--------------- + a | integer | | | | plain | | Partition key + b | text | | | | extended | | Partition key: LIST (a) Number of partitions: 0 @@ -998,10 +998,10 @@ HINT: Specify storage parameters for its leaf partitions, instead. CREATE TABLE arrlp (a int[]) PARTITION BY LIST (a); CREATE TABLE arrlp12 PARTITION OF arrlp FOR VALUES IN ('{1}', '{2}'); \d+ arrlp12 - Table "public.arrlp12" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+-----------+-----------+----------+---------+----------+--------------+------------- - a | integer[] | | | | extended | | + Table "public.arrlp12" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+-----------+-----------+---------------------+---------+----------+--------------+------------- + a | integer[] | | | | extended | | Partition of: arrlp FOR VALUES IN ('{1}', '{2}') Partition constraint: ((a IS NOT NULL) AND ((a = '{1}'::integer[]) OR (a = '{2}'::integer[]))) @@ -1011,10 +1011,10 @@ create table boolspart (a bool) partition by list (a); create table boolspart_t partition of boolspart for values in (true); create table boolspart_f partition of boolspart for values in (false); \d+ boolspart - Partitioned table "public.boolspart" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | boolean | | | | plain | | + Partitioned table "public.boolspart" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | boolean | | | | plain | | Partition key: LIST (a) Partitions: boolspart_f FOR VALUES IN (false), boolspart_t FOR VALUES IN (true) diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out index 0ed94f1d2f..4e29ec7695 100644 --- a/src/test/regress/expected/create_table_like.out +++ b/src/test/regress/expected/create_table_like.out @@ -327,32 +327,32 @@ CREATE TABLE ctlt4 (a text, c text); ALTER TABLE ctlt4 ALTER COLUMN c SET STORAGE EXTERNAL; CREATE TABLE ctlt12_storage (LIKE ctlt1 INCLUDING STORAGE, LIKE ctlt2 INCLUDING STORAGE); \d+ ctlt12_storage - Table "public.ctlt12_storage" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | main | | - b | text | | | | extended | | - c | text | | | | external | | + Table "public.ctlt12_storage" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | main | | + b | text | | | | extended | | + c | text | | | | external | | CREATE TABLE ctlt12_comments (LIKE ctlt1 INCLUDING COMMENTS, LIKE ctlt2 INCLUDING COMMENTS); \d+ ctlt12_comments - Table "public.ctlt12_comments" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | extended | | A - b | text | | | | extended | | B - c | text | | | | extended | | C + Table "public.ctlt12_comments" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | A + b | text | | | | extended | | B + c | text | | | | extended | | C CREATE TABLE ctlt1_inh (LIKE ctlt1 INCLUDING CONSTRAINTS INCLUDING COMMENTS) INHERITS (ctlt1); NOTICE: merging column "a" with inherited definition NOTICE: merging column "b" with inherited definition NOTICE: merging constraint "ctlt1_a_check" with inherited definition \d+ ctlt1_inh - Table "public.ctlt1_inh" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | main | | A - b | text | | | | extended | | B + Table "public.ctlt1_inh" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+----------------------+---------+----------+--------------+------------- + a | text | | ctlt1_inh_a_not_null | | main | | A + b | text | | | | extended | | B Check constraints: "ctlt1_a_check" CHECK (length(a) > 2) Inherits: ctlt1 @@ -366,12 +366,12 @@ SELECT description FROM pg_description, pg_constraint c WHERE classoid = 'pg_con CREATE TABLE ctlt13_inh () INHERITS (ctlt1, ctlt3); NOTICE: merging multiple inherited definitions of column "a" \d+ ctlt13_inh - Table "public.ctlt13_inh" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | main | | - b | text | | | | extended | | - c | text | | | | external | | + Table "public.ctlt13_inh" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+-----------------------+---------+----------+--------------+------------- + a | text | | ctlt13_inh_a_not_null | | main | | + b | text | | | | extended | | + c | text | | | | external | | Check constraints: "ctlt1_a_check" CHECK (length(a) > 2) "ctlt3_a_check" CHECK (length(a) < 5) @@ -382,12 +382,12 @@ Inherits: ctlt1, CREATE TABLE ctlt13_like (LIKE ctlt3 INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING COMMENTS INCLUDING STORAGE) INHERITS (ctlt1); NOTICE: merging column "a" with inherited definition \d+ ctlt13_like - Table "public.ctlt13_like" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | main | | A3 - b | text | | | | extended | | - c | text | | | | external | | C + Table "public.ctlt13_like" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+------------------------+---------+----------+--------------+------------- + a | text | | ctlt13_like_a_not_null | | main | | A3 + b | text | | | | extended | | + c | text | | | | external | | C Indexes: "ctlt13_like_expr_idx" btree ((a || c)) Check constraints: @@ -404,11 +404,11 @@ SELECT description FROM pg_description, pg_constraint c WHERE classoid = 'pg_con CREATE TABLE ctlt_all (LIKE ctlt1 INCLUDING ALL); \d+ ctlt_all - Table "public.ctlt_all" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | main | | A - b | text | | | | extended | | B + Table "public.ctlt_all" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | (primary key) | | main | | A + b | text | | | | extended | | B Indexes: "ctlt_all_pkey" PRIMARY KEY, btree (a) "ctlt_all_b_idx" btree (b) @@ -444,11 +444,11 @@ DETAIL: MAIN versus EXTENDED -- Check that LIKE isn't confused by a system catalog of the same name CREATE TABLE pg_attrdef (LIKE ctlt1 INCLUDING ALL); \d+ public.pg_attrdef - Table "public.pg_attrdef" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | main | | A - b | text | | | | extended | | B + Table "public.pg_attrdef" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | (primary key) | | main | | A + b | text | | | | extended | | B Indexes: "pg_attrdef_pkey" PRIMARY KEY, btree (a) "pg_attrdef_b_idx" btree (b) @@ -466,11 +466,11 @@ CREATE SCHEMA ctl_schema; SET LOCAL search_path = ctl_schema, public; CREATE TABLE ctlt1 (LIKE ctlt1 INCLUDING ALL); \d+ ctlt1 - Table "ctl_schema.ctlt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------+-----------+----------+---------+----------+--------------+------------- - a | text | | not null | | main | | A - b | text | | | | extended | | B + Table "ctl_schema.ctlt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | (primary key) | | main | | A + b | text | | | | extended | | B Indexes: "ctlt1_pkey" PRIMARY KEY, btree (a) "ctlt1_b_idx" btree (b) diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out index 61825ef7d4..dc4bb828ea 100644 --- a/src/test/regress/expected/create_view.out +++ b/src/test/regress/expected/create_view.out @@ -358,14 +358,14 @@ SELECT relname, relkind, reloptions FROM pg_class CREATE VIEW unspecified_types AS SELECT 42 as i, 42.5 as num, 'foo' as u, 'foo'::unknown as u2, null as n; \d+ unspecified_types - View "testviewschm2.unspecified_types" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - i | integer | | | | plain | - num | numeric | | | | main | - u | text | | | | extended | - u2 | text | | | | extended | - n | text | | | | extended | + View "testviewschm2.unspecified_types" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + i | integer | | | | plain | + num | numeric | | | | main | + u | text | | | | extended | + u2 | text | | | | extended | + n | text | | | | extended | View definition: SELECT 42 AS i, 42.5 AS num, @@ -387,13 +387,13 @@ CREATE VIEW tt1 AS ('0123456789', 'abc'::varchar(3), 42.12, 'abc'::varchar(4)) ) vv(a,b,c,d); \d+ tt1 - View "testviewschm2.tt1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+----------------------+-----------+----------+---------+----------+------------- - a | character varying | | | | extended | - b | character varying | | | | extended | - c | numeric | | | | main | - d | character varying(4) | | | | extended | + View "testviewschm2.tt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+----------------------+-----------+---------------------+---------+----------+------------- + a | character varying | | | | extended | + b | character varying | | | | extended | + c | numeric | | | | main | + d | character varying(4) | | | | extended | View definition: SELECT a, b, @@ -433,12 +433,12 @@ CREATE VIEW aliased_view_4 AS select * from temp_view_test.tt1 where exists (select 1 from tt1 where temp_view_test.tt1.y1 = tt1.f1); \d+ aliased_view_1 - View "testviewschm2.aliased_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -449,12 +449,12 @@ View definition: WHERE tt1.f1 = tx1.x1)); \d+ aliased_view_2 - View "testviewschm2.aliased_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -465,12 +465,12 @@ View definition: WHERE a1.f1 = tx1.x1)); \d+ aliased_view_3 - View "testviewschm2.aliased_view_3" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -481,12 +481,12 @@ View definition: WHERE tt1.f1 = a2.x1)); \d+ aliased_view_4 - View "testviewschm2.aliased_view_4" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - y1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + y1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT y1, f2, @@ -498,12 +498,12 @@ View definition: ALTER TABLE tx1 RENAME TO a1; \d+ aliased_view_1 - View "testviewschm2.aliased_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -514,12 +514,12 @@ View definition: WHERE tt1.f1 = a1.x1)); \d+ aliased_view_2 - View "testviewschm2.aliased_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -530,12 +530,12 @@ View definition: WHERE a1.f1 = a1_1.x1)); \d+ aliased_view_3 - View "testviewschm2.aliased_view_3" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -546,12 +546,12 @@ View definition: WHERE tt1.f1 = a2.x1)); \d+ aliased_view_4 - View "testviewschm2.aliased_view_4" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - y1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + y1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT y1, f2, @@ -563,12 +563,12 @@ View definition: ALTER TABLE tt1 RENAME TO a2; \d+ aliased_view_1 - View "testviewschm2.aliased_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -579,12 +579,12 @@ View definition: WHERE a2.f1 = a1.x1)); \d+ aliased_view_2 - View "testviewschm2.aliased_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -595,12 +595,12 @@ View definition: WHERE a1.f1 = a1_1.x1)); \d+ aliased_view_3 - View "testviewschm2.aliased_view_3" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -611,12 +611,12 @@ View definition: WHERE a2.f1 = a2_1.x1)); \d+ aliased_view_4 - View "testviewschm2.aliased_view_4" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - y1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + y1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT y1, f2, @@ -628,12 +628,12 @@ View definition: ALTER TABLE a1 RENAME TO tt1; \d+ aliased_view_1 - View "testviewschm2.aliased_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -644,12 +644,12 @@ View definition: WHERE a2.f1 = tt1.x1)); \d+ aliased_view_2 - View "testviewschm2.aliased_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -660,12 +660,12 @@ View definition: WHERE a1.f1 = tt1.x1)); \d+ aliased_view_3 - View "testviewschm2.aliased_view_3" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -676,12 +676,12 @@ View definition: WHERE a2.f1 = a2_1.x1)); \d+ aliased_view_4 - View "testviewschm2.aliased_view_4" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - y1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + y1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT y1, f2, @@ -694,12 +694,12 @@ View definition: ALTER TABLE a2 RENAME TO tx1; ALTER TABLE tx1 SET SCHEMA temp_view_test; \d+ aliased_view_1 - View "testviewschm2.aliased_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -710,12 +710,12 @@ View definition: WHERE tx1.f1 = tt1.x1)); \d+ aliased_view_2 - View "testviewschm2.aliased_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -726,12 +726,12 @@ View definition: WHERE a1.f1 = tt1.x1)); \d+ aliased_view_3 - View "testviewschm2.aliased_view_3" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -742,12 +742,12 @@ View definition: WHERE tx1.f1 = a2.x1)); \d+ aliased_view_4 - View "testviewschm2.aliased_view_4" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - y1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + y1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT y1, f2, @@ -761,12 +761,12 @@ ALTER TABLE temp_view_test.tt1 RENAME TO tmp1; ALTER TABLE temp_view_test.tmp1 SET SCHEMA testviewschm2; ALTER TABLE tmp1 RENAME TO tx1; \d+ aliased_view_1 - View "testviewschm2.aliased_view_1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -777,12 +777,12 @@ View definition: WHERE tx1.f1 = tt1.x1)); \d+ aliased_view_2 - View "testviewschm2.aliased_view_2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -793,12 +793,12 @@ View definition: WHERE a1.f1 = tt1.x1)); \d+ aliased_view_3 - View "testviewschm2.aliased_view_3" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - f1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + f1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT f1, f2, @@ -809,12 +809,12 @@ View definition: WHERE tx1.f1 = a2.x1)); \d+ aliased_view_4 - View "testviewschm2.aliased_view_4" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+----------+------------- - y1 | integer | | | | plain | - f2 | integer | | | | plain | - f3 | text | | | | extended | + View "testviewschm2.aliased_view_4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+----------+------------- + y1 | integer | | | | plain | + f2 | integer | | | | plain | + f3 | text | | | | extended | View definition: SELECT y1, f2, @@ -830,17 +830,17 @@ select * from (select * from (tbl1 cross join tbl2) same) ss, (tbl3 cross join tbl4) same; \d+ view_of_joins - View "testviewschm2.view_of_joins" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | - b | integer | | | | plain | - c | integer | | | | plain | - d | integer | | | | plain | - e | integer | | | | plain | - f | integer | | | | plain | - g | integer | | | | plain | - h | integer | | | | plain | + View "testviewschm2.view_of_joins" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | + b | integer | | | | plain | + c | integer | | | | plain | + d | integer | | | | plain | + e | integer | | | | plain | + f | integer | | | | plain | + g | integer | | | | plain | + h | integer | | | | plain | View definition: SELECT ss.a, ss.b, @@ -1826,10 +1826,10 @@ create table tt15v_log(o tt15v, n tt15v, incr bool); create rule updlog as on update to tt15v do also insert into tt15v_log values(old, new, row(old,old) < row(new,new)); \d+ tt15v - View "testviewschm2.tt15v" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+-----------------+-----------+----------+---------+----------+------------- - row | nestedcomposite | | | | extended | + View "testviewschm2.tt15v" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+-----------------+-----------+---------------------+---------+----------+------------- + row | nestedcomposite | | | | extended | View definition: SELECT ROW(i.*::int8_tbl)::nestedcomposite AS "row" FROM int8_tbl i; diff --git a/src/test/regress/expected/domain.out b/src/test/regress/expected/domain.out index 11276063bb..f2df4ffc6a 100644 --- a/src/test/regress/expected/domain.out +++ b/src/test/regress/expected/domain.out @@ -316,10 +316,10 @@ explain (verbose, costs off) create rule silly as on delete to dcomptable do instead update dcomptable set d1.r = (d1).r - 1, d1.i = (d1).i + 1 where (d1).i > 0; \d+ dcomptable - Table "public.dcomptable" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+-----------+-----------+----------+---------+----------+--------------+------------- - d1 | dcomptype | | | | extended | | + Table "public.dcomptable" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+-----------+-----------+---------------------+---------+----------+--------------+------------- + d1 | dcomptype | | | | extended | | Indexes: "dcomptable_d1_key" UNIQUE CONSTRAINT, btree (d1) Rules: @@ -476,10 +476,10 @@ create rule silly as on delete to dcomptable do instead update dcomptable set d1[1].r = d1[1].r - 1, d1[1].i = d1[1].i + 1 where d1[1].i > 0; \d+ dcomptable - Table "public.dcomptable" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+------------+-----------+----------+---------+----------+--------------+------------- - d1 | dcomptypea | | | | extended | | + Table "public.dcomptable" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+------------+-----------+---------------------+---------+----------+--------------+------------- + d1 | dcomptypea | | | | extended | | Indexes: "dcomptable_d1_key" UNIQUE CONSTRAINT, btree (d1) Rules: diff --git a/src/test/regress/expected/expressions.out b/src/test/regress/expected/expressions.out index d2c6db1bd5..a0eb6e19df 100644 --- a/src/test/regress/expected/expressions.out +++ b/src/test/regress/expected/expressions.out @@ -127,15 +127,15 @@ create view numeric_view as f2, f2::numeric(16,4) as f2164, f2::numeric as f2n from numeric_tbl; \d+ numeric_view - View "public.numeric_view" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------------+-----------+----------+---------+---------+------------- - f1 | numeric(18,3) | | | | main | - f1164 | numeric(16,4) | | | | main | - f1n | numeric | | | | main | - f2 | numeric | | | | main | - f2164 | numeric(16,4) | | | | main | - f2n | numeric | | | | main | + View "public.numeric_view" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------------+-----------+---------------------+---------+---------+------------- + f1 | numeric(18,3) | | | | main | + f1164 | numeric(16,4) | | | | main | + f1n | numeric | | | | main | + f2 | numeric | | | | main | + f2164 | numeric(16,4) | | | | main | + f2n | numeric | | | | main | View definition: SELECT f1, f1::numeric(16,4) AS f1164, @@ -161,15 +161,15 @@ create view bpchar_view as f2, f2::character(14) as f214, f2::bpchar as f2n from bpchar_tbl; \d+ bpchar_view - View "public.bpchar_view" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------------+-----------+----------+---------+----------+------------- - f1 | character(16) | | | | extended | - f114 | character(14) | | | | extended | - f1n | bpchar | | | | extended | - f2 | bpchar | | | | extended | - f214 | character(14) | | | | extended | - f2n | bpchar | | | | extended | + View "public.bpchar_view" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------------+-----------+---------------------+---------+----------+------------- + f1 | character(16) | | | | extended | + f114 | character(14) | | | | extended | + f1n | bpchar | | | | extended | + f2 | bpchar | | | | extended | + f214 | character(14) | | | | extended | + f2n | bpchar | | | | extended | View definition: SELECT f1, f1::character(14) AS f114, diff --git a/src/test/regress/expected/foreign_data.out b/src/test/regress/expected/foreign_data.out index e90f4f846b..811b2be752 100644 --- a/src/test/regress/expected/foreign_data.out +++ b/src/test/regress/expected/foreign_data.out @@ -733,12 +733,12 @@ CREATE FOREIGN TABLE ft1 ( COMMENT ON FOREIGN TABLE ft1 IS 'ft1'; COMMENT ON COLUMN ft1.c1 IS 'ft1.c1'; \d+ ft1 - Foreign table "public.ft1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+--------------------------------+----------+--------------+------------- - c1 | integer | | not null | | ("param 1" 'val1') | plain | | ft1.c1 - c2 | text | | | | (param2 'val2', param3 'val3') | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+--------------------------------+----------+--------------+------------- + c1 | integer | | ft1_c1_not_null | | ("param 1" 'val1') | plain | | ft1.c1 + c2 | text | | | | (param2 'val2', param3 'val3') | extended | | + c3 | date | | | | | plain | | Check constraints: "ft1_c2_check" CHECK (c2 <> ''::text) "ft1_c3_check" CHECK (c3 >= '01-01-1994'::date AND c3 <= '01-31-1994'::date) @@ -848,19 +848,19 @@ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct = 100); ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1; ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STORAGE PLAIN; \d+ ft1 - Foreign table "public.ft1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+--------------------------------+----------+--------------+------------- - c1 | integer | | not null | | ("param 1" 'val1') | plain | 10000 | - c2 | text | | | | (param2 'val2', param3 'val3') | extended | | - c3 | date | | | | | plain | | - c4 | integer | | | 0 | | plain | | - c5 | integer | | | | | plain | | - c6 | integer | | not null | | | plain | | - c7 | integer | | | | (p1 'v1', p2 'v2') | plain | | - c8 | text | | | | (p2 'V2') | plain | | - c9 | integer | | | | | plain | | - c10 | integer | | | | (p1 'v1') | plain | | + Foreign table "public.ft1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+--------------------------------+----------+--------------+------------- + c1 | integer | | ft1_c1_not_null | | ("param 1" 'val1') | plain | 10000 | + c2 | text | | | | (param2 'val2', param3 'val3') | extended | | + c3 | date | | | | | plain | | + c4 | integer | | | 0 | | plain | | + c5 | integer | | | | | plain | | + c6 | integer | | ft1_c6_not_null | | | plain | | + c7 | integer | | | | (p1 'v1', p2 'v2') | plain | | + c8 | text | | | | (p2 'V2') | plain | | + c9 | integer | | | | | plain | | + c10 | integer | | | | (p1 'v1') | plain | | Check constraints: "ft1_c2_check" CHECK (c2 <> ''::text) "ft1_c3_check" CHECK (c3 >= '01-01-1994'::date AND c3 <= '01-31-1994'::date) @@ -1398,33 +1398,33 @@ CREATE TABLE fd_pt1 ( CREATE FOREIGN TABLE ft2 () INHERITS (fd_pt1) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') Inherits: fd_pt1 DROP FOREIGN TABLE ft2; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | CREATE FOREIGN TABLE ft2 ( c1 integer NOT NULL, @@ -1432,32 +1432,32 @@ CREATE FOREIGN TABLE ft2 ( c3 date ) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') ALTER FOREIGN TABLE ft2 INHERIT fd_pt1; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') Inherits: fd_pt1 @@ -1473,12 +1473,12 @@ NOTICE: merging column "c1" with inherited definition NOTICE: merging column "c2" with inherited definition NOTICE: merging column "c3" with inherited definition \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') Inherits: fd_pt1 @@ -1486,21 +1486,21 @@ Child tables: ct3, ft3, FOREIGN \d+ ct3 - Table "public.ct3" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.ct3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Inherits: ft2 \d+ ft3 - Foreign table "public.ft3" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft3" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft3_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Server: s0 Inherits: ft2 @@ -1511,31 +1511,31 @@ ALTER TABLE fd_pt1 ADD COLUMN c6 integer; ALTER TABLE fd_pt1 ADD COLUMN c7 integer NOT NULL; ALTER TABLE fd_pt1 ADD COLUMN c8 integer; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | - c4 | integer | | | | plain | | - c5 | integer | | | 0 | plain | | - c6 | integer | | | | plain | | - c7 | integer | | not null | | plain | | - c8 | integer | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | + c4 | integer | | | | plain | | + c5 | integer | | | 0 | plain | | + c6 | integer | | | | plain | | + c7 | integer | | fd_pt1_c7_not_null | | plain | | + c8 | integer | | | | plain | | Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | - c4 | integer | | | | | plain | | - c5 | integer | | | 0 | | plain | | - c6 | integer | | | | | plain | | - c7 | integer | | not null | | | plain | | - c8 | integer | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | + c4 | integer | | | | | plain | | + c5 | integer | | | 0 | | plain | | + c6 | integer | | | | | plain | | + c7 | integer | | fd_pt1_c7_not_null | | | plain | | + c8 | integer | | | | | plain | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') Inherits: fd_pt1 @@ -1543,31 +1543,31 @@ Child tables: ct3, ft3, FOREIGN \d+ ct3 - Table "public.ct3" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | - c4 | integer | | | | plain | | - c5 | integer | | | 0 | plain | | - c6 | integer | | | | plain | | - c7 | integer | | not null | | plain | | - c8 | integer | | | | plain | | + Table "public.ct3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | + c4 | integer | | | | plain | | + c5 | integer | | | 0 | plain | | + c6 | integer | | | | plain | | + c7 | integer | | fd_pt1_c7_not_null | | plain | | + c8 | integer | | | | plain | | Inherits: ft2 \d+ ft3 - Foreign table "public.ft3" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | - c4 | integer | | | | | plain | | - c5 | integer | | | 0 | | plain | | - c6 | integer | | | | | plain | | - c7 | integer | | not null | | | plain | | - c8 | integer | | | | | plain | | + Foreign table "public.ft3" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft3_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | + c4 | integer | | | | | plain | | + c5 | integer | | | 0 | | plain | | + c6 | integer | | | | | plain | | + c7 | integer | | fd_pt1_c7_not_null | | | plain | | + c8 | integer | | | | | plain | | Server: s0 Inherits: ft2 @@ -1585,31 +1585,31 @@ ALTER TABLE fd_pt1 ALTER COLUMN c1 SET (n_distinct = 100); ALTER TABLE fd_pt1 ALTER COLUMN c8 SET STATISTICS -1; ALTER TABLE fd_pt1 ALTER COLUMN c8 SET STORAGE EXTERNAL; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | 10000 | - c2 | text | | | | extended | | - c3 | date | | | | plain | | - c4 | integer | | | 0 | plain | | - c5 | integer | | | | plain | | - c6 | integer | | not null | | plain | | - c7 | integer | | | | plain | | - c8 | text | | | | external | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | 10000 | + c2 | text | | | | extended | | + c3 | date | | | | plain | | + c4 | integer | | | 0 | plain | | + c5 | integer | | | | plain | | + c6 | integer | | fd_pt1_c6_not_null | | plain | | + c7 | integer | | | | plain | | + c8 | text | | | | external | | Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | 10000 | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | - c4 | integer | | | 0 | | plain | | - c5 | integer | | | | | plain | | - c6 | integer | | not null | | | plain | | - c7 | integer | | | | | plain | | - c8 | text | | | | | external | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | 10000 | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | + c4 | integer | | | 0 | | plain | | + c5 | integer | | | | | plain | | + c6 | integer | | fd_pt1_c6_not_null | | | plain | | + c7 | integer | | | | | plain | | + c8 | text | | | | | external | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') Inherits: fd_pt1 @@ -1623,21 +1623,21 @@ ALTER TABLE fd_pt1 DROP COLUMN c6; ALTER TABLE fd_pt1 DROP COLUMN c7; ALTER TABLE fd_pt1 DROP COLUMN c8; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | 10000 | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | 10000 | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | 10000 | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | 10000 | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') Inherits: fd_pt1 @@ -1661,24 +1661,24 @@ SELECT relname, conname, contype, conislocal, coninhcount, connoinherit -- child does not inherit NO INHERIT constraints \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | 10000 | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | 10000 | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Check constraints: "fd_pt1chk1" CHECK (c1 > 0) NO INHERIT "fd_pt1chk2" CHECK (c2 <> ''::text) Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | 10000 | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | 10000 | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Check constraints: "fd_pt1chk2" CHECK (c2 <> ''::text) Server: s0 @@ -1708,24 +1708,24 @@ ALTER FOREIGN TABLE ft2 ADD CONSTRAINT fd_pt1chk2 CHECK (c2 <> ''); ALTER FOREIGN TABLE ft2 INHERIT fd_pt1; -- child does not inherit NO INHERIT constraints \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | 10000 | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | 10000 | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Check constraints: "fd_pt1chk1" CHECK (c1 > 0) NO INHERIT "fd_pt1chk2" CHECK (c2 <> ''::text) Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Check constraints: "fd_pt1chk2" CHECK (c2 <> ''::text) Server: s0 @@ -1739,23 +1739,23 @@ ALTER TABLE fd_pt1 DROP CONSTRAINT fd_pt1chk2 CASCADE; INSERT INTO fd_pt1 VALUES (1, 'fd_pt1'::text, '1994-01-01'::date); ALTER TABLE fd_pt1 ADD CONSTRAINT fd_pt1chk3 CHECK (c2 <> '') NOT VALID; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | 10000 | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | 10000 | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Check constraints: "fd_pt1chk3" CHECK (c2 <> ''::text) NOT VALID Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Check constraints: "fd_pt1chk2" CHECK (c2 <> ''::text) "fd_pt1chk3" CHECK (c2 <> ''::text) NOT VALID @@ -1766,23 +1766,23 @@ Inherits: fd_pt1 -- VALIDATE CONSTRAINT need do nothing on foreign tables ALTER TABLE fd_pt1 VALIDATE CONSTRAINT fd_pt1chk3; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | 10000 | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt1_c1_not_null | | plain | 10000 | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Check constraints: "fd_pt1chk3" CHECK (c2 <> ''::text) Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | ft2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Check constraints: "fd_pt1chk2" CHECK (c2 <> ''::text) "fd_pt1chk3" CHECK (c2 <> ''::text) @@ -1797,23 +1797,23 @@ ALTER TABLE fd_pt1 RENAME COLUMN c3 TO f3; -- changes name of a constraint recursively ALTER TABLE fd_pt1 RENAME CONSTRAINT fd_pt1chk3 TO f2_check; \d+ fd_pt1 - Table "public.fd_pt1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - f1 | integer | | not null | | plain | 10000 | - f2 | text | | | | extended | | - f3 | date | | | | plain | | + Table "public.fd_pt1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + f1 | integer | | fd_pt1_c1_not_null | | plain | 10000 | + f2 | text | | | | extended | | + f3 | date | | | | plain | | Check constraints: "f2_check" CHECK (f2 <> ''::text) Child tables: ft2, FOREIGN \d+ ft2 - Foreign table "public.ft2" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - f1 | integer | | not null | | | plain | | - f2 | text | | | | | extended | | - f3 | date | | | | | plain | | + Foreign table "public.ft2" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + f1 | integer | | ft2_c1_not_null | | | plain | | + f2 | text | | | | | extended | | + f3 | date | | | | | plain | | Check constraints: "f2_check" CHECK (f2 <> ''::text) "fd_pt1chk2" CHECK (f2 <> ''::text) @@ -1856,22 +1856,22 @@ CREATE TABLE fd_pt2 ( CREATE FOREIGN TABLE fd_pt2_1 PARTITION OF fd_pt2 FOR VALUES IN (1) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); \d+ fd_pt2 - Partitioned table "public.fd_pt2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Partitioned table "public.fd_pt2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt2_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Partition key: LIST (c1) Partitions: fd_pt2_1 FOR VALUES IN (1), FOREIGN \d+ fd_pt2_1 - Foreign table "public.fd_pt2_1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.fd_pt2_1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt2_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Partition of: fd_pt2 FOR VALUES IN (1) Partition constraint: ((c1 IS NOT NULL) AND (c1 = 1)) Server: s0 @@ -1886,13 +1886,13 @@ CREATE FOREIGN TABLE fd_pt2_1 ( c4 char ) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); \d+ fd_pt2_1 - Foreign table "public.fd_pt2_1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+--------------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | - c4 | character(1) | | | | | extended | | + Foreign table "public.fd_pt2_1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+--------------+-----------+----------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt2_1_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | + c4 | character(1) | | | | | extended | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') @@ -1901,12 +1901,12 @@ ERROR: table "fd_pt2_1" contains column "c4" not found in parent "fd_pt2" DETAIL: The new partition may contain only the columns present in parent. DROP FOREIGN TABLE fd_pt2_1; \d+ fd_pt2 - Partitioned table "public.fd_pt2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Partitioned table "public.fd_pt2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt2_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Partition key: LIST (c1) Number of partitions: 0 @@ -1916,34 +1916,34 @@ CREATE FOREIGN TABLE fd_pt2_1 ( c3 date ) SERVER s0 OPTIONS (delimiter ',', quote '"', "be quoted" 'value'); \d+ fd_pt2_1 - Foreign table "public.fd_pt2_1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.fd_pt2_1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+----------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt2_1_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Server: s0 FDW options: (delimiter ',', quote '"', "be quoted" 'value') -- no attach partition validation occurs for foreign tables ALTER TABLE fd_pt2 ATTACH PARTITION fd_pt2_1 FOR VALUES IN (1); \d+ fd_pt2 - Partitioned table "public.fd_pt2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Partitioned table "public.fd_pt2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt2_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Partition key: LIST (c1) Partitions: fd_pt2_1 FOR VALUES IN (1), FOREIGN \d+ fd_pt2_1 - Foreign table "public.fd_pt2_1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | | | | plain | | + Foreign table "public.fd_pt2_1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+----------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt2_1_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | | | | plain | | Partition of: fd_pt2 FOR VALUES IN (1) Partition constraint: ((c1 IS NOT NULL) AND (c1 = 1)) Server: s0 @@ -1956,22 +1956,22 @@ ERROR: cannot add column to a partition ALTER TABLE fd_pt2_1 ALTER c3 SET NOT NULL; ALTER TABLE fd_pt2_1 ADD CONSTRAINT p21chk CHECK (c2 <> ''); \d+ fd_pt2 - Partitioned table "public.fd_pt2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | | | extended | | - c3 | date | | | | plain | | + Partitioned table "public.fd_pt2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt2_c1_not_null | | plain | | + c2 | text | | | | extended | | + c3 | date | | | | plain | | Partition key: LIST (c1) Partitions: fd_pt2_1 FOR VALUES IN (1), FOREIGN \d+ fd_pt2_1 - Foreign table "public.fd_pt2_1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | not null | | | plain | | + Foreign table "public.fd_pt2_1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+----------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt2_1_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | fd_pt2_1_c3_not_null | | | plain | | Partition of: fd_pt2 FOR VALUES IN (1) Partition constraint: ((c1 IS NOT NULL) AND (c1 = 1)) Check constraints: @@ -1986,22 +1986,22 @@ ERROR: column "c1" is marked NOT NULL in parent table ALTER TABLE fd_pt2 DETACH PARTITION fd_pt2_1; ALTER TABLE fd_pt2 ALTER c2 SET NOT NULL; \d+ fd_pt2 - Partitioned table "public.fd_pt2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | not null | | extended | | - c3 | date | | | | plain | | + Partitioned table "public.fd_pt2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt2_c1_not_null | | plain | | + c2 | text | | fd_pt2_c2_not_null | | extended | | + c3 | date | | | | plain | | Partition key: LIST (c1) Number of partitions: 0 \d+ fd_pt2_1 - Foreign table "public.fd_pt2_1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | | | | extended | | - c3 | date | | not null | | | plain | | + Foreign table "public.fd_pt2_1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+----------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt2_1_c1_not_null | | | plain | | + c2 | text | | | | | extended | | + c3 | date | | fd_pt2_1_c3_not_null | | | plain | | Check constraints: "p21chk" CHECK (c2 <> ''::text) Server: s0 @@ -2014,24 +2014,24 @@ ALTER TABLE fd_pt2 ATTACH PARTITION fd_pt2_1 FOR VALUES IN (1); ALTER TABLE fd_pt2 DETACH PARTITION fd_pt2_1; ALTER TABLE fd_pt2 ADD CONSTRAINT fd_pt2chk1 CHECK (c1 > 0); \d+ fd_pt2 - Partitioned table "public.fd_pt2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - c1 | integer | | not null | | plain | | - c2 | text | | not null | | extended | | - c3 | date | | | | plain | | + Partitioned table "public.fd_pt2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + c1 | integer | | fd_pt2_c1_not_null | | plain | | + c2 | text | | fd_pt2_c2_not_null | | extended | | + c3 | date | | | | plain | | Partition key: LIST (c1) Check constraints: "fd_pt2chk1" CHECK (c1 > 0) Number of partitions: 0 \d+ fd_pt2_1 - Foreign table "public.fd_pt2_1" - Column | Type | Collation | Nullable | Default | FDW options | Storage | Stats target | Description ---------+---------+-----------+----------+---------+-------------+----------+--------------+------------- - c1 | integer | | not null | | | plain | | - c2 | text | | not null | | | extended | | - c3 | date | | not null | | | plain | | + Foreign table "public.fd_pt2_1" + Column | Type | Collation | NOT NULL Constraint | Default | FDW options | Storage | Stats target | Description +--------+---------+-----------+----------------------+---------+-------------+----------+--------------+------------- + c1 | integer | | fd_pt2_1_c1_not_null | | | plain | | + c2 | text | | fd_pt2_1_c2_not_null | | | extended | | + c3 | date | | fd_pt2_1_c3_not_null | | | plain | | Check constraints: "p21chk" CHECK (c2 <> ''::text) Server: s0 diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated.out index 702774d644..cbffc51aa0 100644 --- a/src/test/regress/expected/generated.out +++ b/src/test/regress/expected/generated.out @@ -309,12 +309,12 @@ ERROR: column "b" inherits from generated column but specifies identity CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1); -- ok, overrides parent NOTICE: merging column "b" with inherited definition \d+ gtestx - Table "public.gtestx" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+-------------------------------------+---------+--------------+------------- - a | integer | | not null | | plain | | - b | integer | | | generated always as (a * 22) stored | plain | | - x | integer | | | | plain | | + Table "public.gtestx" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+-------------------------------------+---------+--------------+------------- + a | integer | | gtestx_a_not_null | | plain | | + b | integer | | | generated always as (a * 22) stored | plain | | + x | integer | | | | plain | | Inherits: gtest1 CREATE TABLE gtestxx_1 (a int NOT NULL, b int); diff --git a/src/test/regress/expected/identity.out b/src/test/regress/expected/identity.out index 5f03d8e14f..d9efe01298 100644 --- a/src/test/regress/expected/identity.out +++ b/src/test/regress/expected/identity.out @@ -498,14 +498,14 @@ TABLE itest8; (2 rows) \d+ itest8 - Table "public.itest8" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+----------------------------------+---------+--------------+------------- - f1 | integer | | | | plain | | - f2 | integer | | not null | generated always as identity | plain | | - f3 | integer | | not null | generated by default as identity | plain | | - f4 | bigint | | not null | generated always as identity | plain | | - f5 | bigint | | | | plain | | + Table "public.itest8" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+----------------------------------+---------+--------------+------------- + f1 | integer | | | | plain | | + f2 | integer | | itest8_f2_not_null | generated always as identity | plain | | + f3 | integer | | itest8_f3_not_null | generated by default as identity | plain | | + f4 | bigint | | itest8_f4_not_null | generated always as identity | plain | | + f5 | bigint | | | | plain | | \d itest8_f2_seq Sequence "public.itest8_f2_seq" diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out index 4777499c21..bf402fe291 100644 --- a/src/test/regress/expected/inherit.out +++ b/src/test/regress/expected/inherit.out @@ -1059,13 +1059,13 @@ ALTER TABLE inhts RENAME aa TO aaa; -- to be failed ERROR: cannot rename inherited column "aa" ALTER TABLE inhts RENAME d TO dd; \d+ inhts - Table "public.inhts" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - aa | integer | | | | plain | | - b | integer | | | | plain | | - c | integer | | | | plain | | - dd | integer | | | | plain | | + Table "public.inhts" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + aa | integer | | | | plain | | + b | integer | | | | plain | | + c | integer | | | | plain | | + dd | integer | | | | plain | | Inherits: inht1, inhs1 @@ -1078,14 +1078,14 @@ NOTICE: merging multiple inherited definitions of column "aa" NOTICE: merging multiple inherited definitions of column "b" ALTER TABLE inht1 RENAME aa TO aaa; \d+ inht4 - Table "public.inht4" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - aaa | integer | | | | plain | | - b | integer | | | | plain | | - x | integer | | | | plain | | - y | integer | | | | plain | | - z | integer | | | | plain | | + Table "public.inht4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + aaa | integer | | | | plain | | + b | integer | | | | plain | | + x | integer | | | | plain | | + y | integer | | | | plain | | + z | integer | | | | plain | | Inherits: inht2, inht3 @@ -1095,14 +1095,14 @@ ALTER TABLE inht1 RENAME aaa TO aaaa; ALTER TABLE inht1 RENAME b TO bb; -- to be failed ERROR: cannot rename inherited column "b" \d+ inhts - Table "public.inhts" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - aaaa | integer | | | | plain | | - b | integer | | | | plain | | - x | integer | | | | plain | | - c | integer | | | | plain | | - d | integer | | | | plain | | + Table "public.inhts" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + aaaa | integer | | | | plain | | + b | integer | | | | plain | | + x | integer | | | | plain | | + c | integer | | | | plain | | + d | integer | | | | plain | | Inherits: inht2, inhs1 @@ -1142,33 +1142,33 @@ drop cascades to table inht4 CREATE TABLE test_constraints (id int, val1 varchar, val2 int, UNIQUE(val1, val2)); CREATE TABLE test_constraints_inh () INHERITS (test_constraints); \d+ test_constraints - Table "public.test_constraints" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+--------------+------------- - id | integer | | | | plain | | - val1 | character varying | | | | extended | | - val2 | integer | | | | plain | | + Table "public.test_constraints" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+--------------+------------- + id | integer | | | | plain | | + val1 | character varying | | | | extended | | + val2 | integer | | | | plain | | Indexes: "test_constraints_val1_val2_key" UNIQUE CONSTRAINT, btree (val1, val2) Child tables: test_constraints_inh ALTER TABLE ONLY test_constraints DROP CONSTRAINT test_constraints_val1_val2_key; \d+ test_constraints - Table "public.test_constraints" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+--------------+------------- - id | integer | | | | plain | | - val1 | character varying | | | | extended | | - val2 | integer | | | | plain | | + Table "public.test_constraints" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+--------------+------------- + id | integer | | | | plain | | + val1 | character varying | | | | extended | | + val2 | integer | | | | plain | | Child tables: test_constraints_inh \d+ test_constraints_inh - Table "public.test_constraints_inh" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+--------------+------------- - id | integer | | | | plain | | - val1 | character varying | | | | extended | | - val2 | integer | | | | plain | | + Table "public.test_constraints_inh" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+--------------+------------- + id | integer | | | | plain | | + val1 | character varying | | | | extended | | + val2 | integer | | | | plain | | Inherits: test_constraints DROP TABLE test_constraints_inh; @@ -1179,27 +1179,27 @@ CREATE TABLE test_ex_constraints ( ); CREATE TABLE test_ex_constraints_inh () INHERITS (test_ex_constraints); \d+ test_ex_constraints - Table "public.test_ex_constraints" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+--------+-----------+----------+---------+---------+--------------+------------- - c | circle | | | | plain | | + Table "public.test_ex_constraints" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+--------+-----------+---------------------+---------+---------+--------------+------------- + c | circle | | | | plain | | Indexes: "test_ex_constraints_c_excl" EXCLUDE USING gist (c WITH &&) Child tables: test_ex_constraints_inh ALTER TABLE test_ex_constraints DROP CONSTRAINT test_ex_constraints_c_excl; \d+ test_ex_constraints - Table "public.test_ex_constraints" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+--------+-----------+----------+---------+---------+--------------+------------- - c | circle | | | | plain | | + Table "public.test_ex_constraints" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+--------+-----------+---------------------+---------+---------+--------------+------------- + c | circle | | | | plain | | Child tables: test_ex_constraints_inh \d+ test_ex_constraints_inh - Table "public.test_ex_constraints_inh" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+--------+-----------+----------+---------+---------+--------------+------------- - c | circle | | | | plain | | + Table "public.test_ex_constraints_inh" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+--------+-----------+---------------------+---------+---------+--------------+------------- + c | circle | | | | plain | | Inherits: test_ex_constraints DROP TABLE test_ex_constraints_inh; @@ -1209,37 +1209,37 @@ CREATE TABLE test_primary_constraints(id int PRIMARY KEY); CREATE TABLE test_foreign_constraints(id1 int REFERENCES test_primary_constraints(id)); CREATE TABLE test_foreign_constraints_inh () INHERITS (test_foreign_constraints); \d+ test_primary_constraints - Table "public.test_primary_constraints" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - id | integer | | not null | | plain | | + Table "public.test_primary_constraints" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + id | integer | | (primary key) | | plain | | Indexes: "test_primary_constraints_pkey" PRIMARY KEY, btree (id) Referenced by: TABLE "test_foreign_constraints" CONSTRAINT "test_foreign_constraints_id1_fkey" FOREIGN KEY (id1) REFERENCES test_primary_constraints(id) \d+ test_foreign_constraints - Table "public.test_foreign_constraints" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - id1 | integer | | | | plain | | + Table "public.test_foreign_constraints" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + id1 | integer | | | | plain | | Foreign-key constraints: "test_foreign_constraints_id1_fkey" FOREIGN KEY (id1) REFERENCES test_primary_constraints(id) Child tables: test_foreign_constraints_inh ALTER TABLE test_foreign_constraints DROP CONSTRAINT test_foreign_constraints_id1_fkey; \d+ test_foreign_constraints - Table "public.test_foreign_constraints" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - id1 | integer | | | | plain | | + Table "public.test_foreign_constraints" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + id1 | integer | | | | plain | | Child tables: test_foreign_constraints_inh \d+ test_foreign_constraints_inh - Table "public.test_foreign_constraints_inh" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - id1 | integer | | | | plain | | + Table "public.test_foreign_constraints_inh" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + id1 | integer | | | | plain | | Inherits: test_foreign_constraints DROP TABLE test_foreign_constraints_inh; diff --git a/src/test/regress/expected/insert.out b/src/test/regress/expected/insert.out index dd4354fc7d..7633486814 100644 --- a/src/test/regress/expected/insert.out +++ b/src/test/regress/expected/insert.out @@ -163,11 +163,11 @@ create rule irule3 as on insert to inserttest2 do also insert into inserttest (f4[1].if1, f4[1].if2[2]) select new.f1, new.f2; \d+ inserttest2 - Table "public.inserttest2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+--------+-----------+----------+---------+----------+--------------+------------- - f1 | bigint | | | | plain | | - f2 | text | | | | extended | | + Table "public.inserttest2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+--------+-----------+---------------------+---------+----------+--------------+------------- + f1 | bigint | | | | plain | | + f2 | text | | | | extended | | Rules: irule1 AS ON INSERT TO inserttest2 DO INSERT INTO inserttest (f3.if2[1], f3.if2[2]) @@ -447,11 +447,11 @@ from hash_parted order by part; -- test \d+ output on a table which has both partitioned and unpartitioned -- partitions \d+ list_parted - Partitioned table "public.list_parted" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Partitioned table "public.list_parted" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition key: LIST (lower(a)) Partitions: part_aa_bb FOR VALUES IN ('aa', 'bb'), part_cc_dd FOR VALUES IN ('cc', 'dd'), @@ -469,10 +469,10 @@ drop table hash_parted; create table list_parted (a int) partition by list (a); create table part_default partition of list_parted default; \d+ part_default - Table "public.part_default" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | + Table "public.part_default" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | Partition of: list_parted DEFAULT No partition constraint @@ -852,11 +852,11 @@ create table mcrparted6_common_ge_10 partition of mcrparted for values from ('co create table mcrparted7_gt_common_lt_d partition of mcrparted for values from ('common', maxvalue) to ('d', minvalue); create table mcrparted8_ge_d partition of mcrparted for values from ('d', minvalue) to (maxvalue, maxvalue); \d+ mcrparted - Partitioned table "public.mcrparted" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Partitioned table "public.mcrparted" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition key: RANGE (a, b) Partitions: mcrparted1_lt_b FOR VALUES FROM (MINVALUE, MINVALUE) TO ('b', MINVALUE), mcrparted2_b FOR VALUES FROM ('b', MINVALUE) TO ('c', MINVALUE), @@ -868,74 +868,74 @@ Partitions: mcrparted1_lt_b FOR VALUES FROM (MINVALUE, MINVALUE) TO ('b', MINVAL mcrparted8_ge_d FOR VALUES FROM ('d', MINVALUE) TO (MAXVALUE, MAXVALUE) \d+ mcrparted1_lt_b - Table "public.mcrparted1_lt_b" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted1_lt_b" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM (MINVALUE, MINVALUE) TO ('b', MINVALUE) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a < 'b'::text)) \d+ mcrparted2_b - Table "public.mcrparted2_b" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted2_b" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM ('b', MINVALUE) TO ('c', MINVALUE) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a >= 'b'::text) AND (a < 'c'::text)) \d+ mcrparted3_c_to_common - Table "public.mcrparted3_c_to_common" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted3_c_to_common" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM ('c', MINVALUE) TO ('common', MINVALUE) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a >= 'c'::text) AND (a < 'common'::text)) \d+ mcrparted4_common_lt_0 - Table "public.mcrparted4_common_lt_0" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted4_common_lt_0" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM ('common', MINVALUE) TO ('common', 0) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a = 'common'::text) AND (b < 0)) \d+ mcrparted5_common_0_to_10 - Table "public.mcrparted5_common_0_to_10" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted5_common_0_to_10" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM ('common', 0) TO ('common', 10) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a = 'common'::text) AND (b >= 0) AND (b < 10)) \d+ mcrparted6_common_ge_10 - Table "public.mcrparted6_common_ge_10" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted6_common_ge_10" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM ('common', 10) TO ('common', MAXVALUE) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a = 'common'::text) AND (b >= 10)) \d+ mcrparted7_gt_common_lt_d - Table "public.mcrparted7_gt_common_lt_d" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted7_gt_common_lt_d" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM ('common', MAXVALUE) TO ('d', MINVALUE) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a > 'common'::text) AND (a < 'd'::text)) \d+ mcrparted8_ge_d - Table "public.mcrparted8_ge_d" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | integer | | | | plain | | + Table "public.mcrparted8_ge_d" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | integer | | | | plain | | Partition of: mcrparted FOR VALUES FROM ('d', MINVALUE) TO (MAXVALUE, MAXVALUE) Partition constraint: ((a IS NOT NULL) AND (b IS NOT NULL) AND (a >= 'd'::text)) diff --git a/src/test/regress/expected/limit.out b/src/test/regress/expected/limit.out index a2cd0f9f5b..3ba4ea6656 100644 --- a/src/test/regress/expected/limit.out +++ b/src/test/regress/expected/limit.out @@ -633,10 +633,10 @@ ERROR: WITH TIES cannot be specified without ORDER BY clause CREATE VIEW limit_thousand_v_1 AS SELECT thousand FROM onek WHERE thousand < 995 ORDER BY thousand FETCH FIRST 5 ROWS WITH TIES OFFSET 10; \d+ limit_thousand_v_1 - View "public.limit_thousand_v_1" - Column | Type | Collation | Nullable | Default | Storage | Description -----------+---------+-----------+----------+---------+---------+------------- - thousand | integer | | | | plain | + View "public.limit_thousand_v_1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +----------+---------+-----------+---------------------+---------+---------+------------- + thousand | integer | | | | plain | View definition: SELECT thousand FROM onek @@ -648,10 +648,10 @@ View definition: CREATE VIEW limit_thousand_v_2 AS SELECT thousand FROM onek WHERE thousand < 995 ORDER BY thousand OFFSET 10 FETCH FIRST 5 ROWS ONLY; \d+ limit_thousand_v_2 - View "public.limit_thousand_v_2" - Column | Type | Collation | Nullable | Default | Storage | Description -----------+---------+-----------+----------+---------+---------+------------- - thousand | integer | | | | plain | + View "public.limit_thousand_v_2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +----------+---------+-----------+---------------------+---------+---------+------------- + thousand | integer | | | | plain | View definition: SELECT thousand FROM onek @@ -666,10 +666,10 @@ ERROR: row count cannot be null in FETCH FIRST ... WITH TIES clause CREATE VIEW limit_thousand_v_3 AS SELECT thousand FROM onek WHERE thousand < 995 ORDER BY thousand FETCH FIRST (NULL+1) ROWS WITH TIES; \d+ limit_thousand_v_3 - View "public.limit_thousand_v_3" - Column | Type | Collation | Nullable | Default | Storage | Description -----------+---------+-----------+----------+---------+---------+------------- - thousand | integer | | | | plain | + View "public.limit_thousand_v_3" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +----------+---------+-----------+---------------------+---------+---------+------------- + thousand | integer | | | | plain | View definition: SELECT thousand FROM onek @@ -680,10 +680,10 @@ View definition: CREATE VIEW limit_thousand_v_4 AS SELECT thousand FROM onek WHERE thousand < 995 ORDER BY thousand FETCH FIRST NULL ROWS ONLY; \d+ limit_thousand_v_4 - View "public.limit_thousand_v_4" - Column | Type | Collation | Nullable | Default | Storage | Description -----------+---------+-----------+----------+---------+---------+------------- - thousand | integer | | | | plain | + View "public.limit_thousand_v_4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +----------+---------+-----------+---------------------+---------+---------+------------- + thousand | integer | | | | plain | View definition: SELECT thousand FROM onek diff --git a/src/test/regress/expected/matview.out b/src/test/regress/expected/matview.out index 87b6e569a5..de5b8e8004 100644 --- a/src/test/regress/expected/matview.out +++ b/src/test/regress/expected/matview.out @@ -94,11 +94,11 @@ CREATE MATERIALIZED VIEW mvtest_bb AS SELECT * FROM mvtest_tvvmv; CREATE INDEX mvtest_aa ON mvtest_bb (grandtot); -- check that plans seem reasonable \d+ mvtest_tvm - Materialized view "public.mvtest_tvm" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - type | text | | | | extended | | - totamt | numeric | | | | main | | + Materialized view "public.mvtest_tvm" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + type | text | | | | extended | | + totamt | numeric | | | | main | | View definition: SELECT type, totamt @@ -106,11 +106,11 @@ View definition: ORDER BY type; \d+ mvtest_tvm - Materialized view "public.mvtest_tvm" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - type | text | | | | extended | | - totamt | numeric | | | | main | | + Materialized view "public.mvtest_tvm" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + type | text | | | | extended | | + totamt | numeric | | | | main | | View definition: SELECT type, totamt @@ -118,19 +118,19 @@ View definition: ORDER BY type; \d+ mvtest_tvvm - Materialized view "public.mvtest_tvvm" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------+---------+-----------+----------+---------+---------+--------------+------------- - grandtot | numeric | | | | main | | + Materialized view "public.mvtest_tvvm" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------+---------+-----------+---------------------+---------+---------+--------------+------------- + grandtot | numeric | | | | main | | View definition: SELECT grandtot FROM mvtest_tvv; \d+ mvtest_bb - Materialized view "public.mvtest_bb" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------+---------+-----------+----------+---------+---------+--------------+------------- - grandtot | numeric | | | | main | | + Materialized view "public.mvtest_bb" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------+---------+-----------+---------------------+---------+---------+--------------+------------- + grandtot | numeric | | | | main | | Indexes: "mvtest_aa" btree (grandtot) View definition: @@ -142,10 +142,10 @@ CREATE SCHEMA mvtest_mvschema; ALTER MATERIALIZED VIEW mvtest_tvm SET SCHEMA mvtest_mvschema; \d+ mvtest_tvm \d+ mvtest_tvmm - Materialized view "public.mvtest_tvmm" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------+---------+-----------+----------+---------+---------+--------------+------------- - grandtot | numeric | | | | main | | + Materialized view "public.mvtest_tvmm" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------+---------+-----------+---------------------+---------+---------+--------------+------------- + grandtot | numeric | | | | main | | Indexes: "mvtest_tvmm_expr" UNIQUE, btree ((grandtot > 0::numeric)) "mvtest_tvmm_pred" UNIQUE, btree (grandtot) WHERE grandtot < 0::numeric @@ -155,11 +155,11 @@ View definition: SET search_path = mvtest_mvschema, public; \d+ mvtest_tvm - Materialized view "mvtest_mvschema.mvtest_tvm" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - type | text | | | | extended | | - totamt | numeric | | | | main | | + Materialized view "mvtest_mvschema.mvtest_tvm" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + type | text | | | | extended | | + totamt | numeric | | | | main | | View definition: SELECT type, totamt @@ -340,11 +340,11 @@ ROLLBACK; CREATE VIEW mvtest_vt1 AS SELECT 1 moo; CREATE VIEW mvtest_vt2 AS SELECT moo, 2*moo FROM mvtest_vt1 UNION ALL SELECT moo, 3*moo FROM mvtest_vt1; \d+ mvtest_vt2 - View "public.mvtest_vt2" - Column | Type | Collation | Nullable | Default | Storage | Description -----------+---------+-----------+----------+---------+---------+------------- - moo | integer | | | | plain | - ?column? | integer | | | | plain | + View "public.mvtest_vt2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +----------+---------+-----------+---------------------+---------+---------+------------- + moo | integer | | | | plain | + ?column? | integer | | | | plain | View definition: SELECT mvtest_vt1.moo, 2 * mvtest_vt1.moo AS "?column?" @@ -356,11 +356,11 @@ UNION ALL CREATE MATERIALIZED VIEW mv_test2 AS SELECT moo, 2*moo FROM mvtest_vt2 UNION ALL SELECT moo, 3*moo FROM mvtest_vt2; \d+ mv_test2 - Materialized view "public.mv_test2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description -----------+---------+-----------+----------+---------+---------+--------------+------------- - moo | integer | | | | plain | | - ?column? | integer | | | | plain | | + Materialized view "public.mv_test2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +----------+---------+-----------+---------------------+---------+---------+--------------+------------- + moo | integer | | | | plain | | + ?column? | integer | | | | plain | | View definition: SELECT mvtest_vt2.moo, 2 * mvtest_vt2.moo AS "?column?" @@ -493,14 +493,14 @@ drop cascades to materialized view mvtest_mv_v_4 CREATE MATERIALIZED VIEW mv_unspecified_types AS SELECT 42 as i, 42.5 as num, 'foo' as u, 'foo'::unknown as u2, null as n; \d+ mv_unspecified_types - Materialized view "public.mv_unspecified_types" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - i | integer | | | | plain | | - num | numeric | | | | main | | - u | text | | | | extended | | - u2 | text | | | | extended | | - n | text | | | | extended | | + Materialized view "public.mv_unspecified_types" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + i | integer | | | | plain | | + num | numeric | | | | main | | + u | text | | | | extended | | + u2 | text | | | | extended | | + n | text | | | | extended | | View definition: SELECT 42 AS i, 42.5 AS num, diff --git a/src/test/regress/expected/polymorphism.out b/src/test/regress/expected/polymorphism.out index bf08e40ed8..bd395d2291 100644 --- a/src/test/regress/expected/polymorphism.out +++ b/src/test/regress/expected/polymorphism.out @@ -1793,13 +1793,13 @@ select * from dfview; (5 rows) \d+ dfview - View "public.dfview" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+--------+-----------+----------+---------+---------+------------- - q1 | bigint | | | | plain | - q2 | bigint | | | | plain | - c3 | bigint | | | | plain | - c4 | bigint | | | | plain | + View "public.dfview" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+--------+-----------+---------------------+---------+---------+------------- + q1 | bigint | | | | plain | + q2 | bigint | | | | plain | + c3 | bigint | | | | plain | + c4 | bigint | | | | plain | View definition: SELECT q1, q2, diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out index 8fc62cebd2..b5a34a9a7b 100644 --- a/src/test/regress/expected/psql.out +++ b/src/test/regress/expected/psql.out @@ -2857,34 +2857,34 @@ CREATE TABLE tbl_heap(f1 int, f2 char(100)) using heap; CREATE VIEW view_heap_psql AS SELECT f1 from tbl_heap_psql; CREATE MATERIALIZED VIEW mat_view_heap_psql USING heap_psql AS SELECT f1 from tbl_heap_psql; \d+ tbl_heap_psql - Table "tableam_display.tbl_heap_psql" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+----------------+-----------+----------+---------+----------+--------------+------------- - f1 | integer | | | | plain | | - f2 | character(100) | | | | extended | | + Table "tableam_display.tbl_heap_psql" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+----------------+-----------+---------------------+---------+----------+--------------+------------- + f1 | integer | | | | plain | | + f2 | character(100) | | | | extended | | \d+ tbl_heap - Table "tableam_display.tbl_heap" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+----------------+-----------+----------+---------+----------+--------------+------------- - f1 | integer | | | | plain | | - f2 | character(100) | | | | extended | | + Table "tableam_display.tbl_heap" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+----------------+-----------+---------------------+---------+----------+--------------+------------- + f1 | integer | | | | plain | | + f2 | character(100) | | | | extended | | \set HIDE_TABLEAM off \d+ tbl_heap_psql - Table "tableam_display.tbl_heap_psql" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+----------------+-----------+----------+---------+----------+--------------+------------- - f1 | integer | | | | plain | | - f2 | character(100) | | | | extended | | + Table "tableam_display.tbl_heap_psql" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+----------------+-----------+---------------------+---------+----------+--------------+------------- + f1 | integer | | | | plain | | + f2 | character(100) | | | | extended | | Access method: heap_psql \d+ tbl_heap - Table "tableam_display.tbl_heap" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+----------------+-----------+----------+---------+----------+--------------+------------- - f1 | integer | | | | plain | | - f2 | character(100) | | | | extended | | + Table "tableam_display.tbl_heap" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+----------------+-----------+---------------------+---------+----------+--------------+------------- + f1 | integer | | | | plain | | + f2 | character(100) | | | | extended | | Access method: heap -- AM is displayed for tables, indexes and materialized views. diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out index 427f87ea07..62c790c622 100644 --- a/src/test/regress/expected/publication.out +++ b/src/test/regress/expected/publication.out @@ -175,11 +175,11 @@ SELECT pubname, puballtables FROM pg_publication WHERE pubname = 'testpub_forall (1 row) \d+ testpub_tbl2 - Table "public.testpub_tbl2" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('testpub_tbl2_id_seq'::regclass) | plain | | - data | text | | | | extended | | + Table "public.testpub_tbl2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+--------------------------+------------------------------------------+----------+--------------+------------- + id | integer | | testpub_tbl2_id_not_null | nextval('testpub_tbl2_id_seq'::regclass) | plain | | + data | text | | | | extended | | Indexes: "testpub_tbl2_pkey" PRIMARY KEY, btree (id) Publications: @@ -735,12 +735,12 @@ UPDATE testpub_tbl6 SET a = 1; CREATE TABLE testpub_tbl7 (a int primary key, b text, c text); ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl7 (a, b); \d+ testpub_tbl7 - Table "public.testpub_tbl7" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | integer | | not null | | plain | | - b | text | | | | extended | | - c | text | | | | extended | | + Table "public.testpub_tbl7" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | integer | | (primary key) | | plain | | + b | text | | | | extended | | + c | text | | | | extended | | Indexes: "testpub_tbl7_pkey" PRIMARY KEY, btree (a) Publications: @@ -749,12 +749,12 @@ Publications: -- ok: the column list is the same, we should skip this table (or at least not fail) ALTER PUBLICATION testpub_fortable SET TABLE testpub_tbl7 (a, b); \d+ testpub_tbl7 - Table "public.testpub_tbl7" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | integer | | not null | | plain | | - b | text | | | | extended | | - c | text | | | | extended | | + Table "public.testpub_tbl7" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | integer | | (primary key) | | plain | | + b | text | | | | extended | | + c | text | | | | extended | | Indexes: "testpub_tbl7_pkey" PRIMARY KEY, btree (a) Publications: @@ -763,12 +763,12 @@ Publications: -- ok: the column list changes, make sure the catalog gets updated ALTER PUBLICATION testpub_fortable SET TABLE testpub_tbl7 (a, c); \d+ testpub_tbl7 - Table "public.testpub_tbl7" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+----------+--------------+------------- - a | integer | | not null | | plain | | - b | text | | | | extended | | - c | text | | | | extended | | + Table "public.testpub_tbl7" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+----------+--------------+------------- + a | integer | | (primary key) | | plain | | + b | text | | | | extended | | + c | text | | | | extended | | Indexes: "testpub_tbl7_pkey" PRIMARY KEY, btree (a) Publications: @@ -899,12 +899,12 @@ Tables: "public.testpub_tbl_both_filters" (a, c) WHERE (c <> 1) \d+ testpub_tbl_both_filters - Table "public.testpub_tbl_both_filters" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | not null | | plain | | - b | integer | | | | plain | | - c | integer | | not null | | plain | | + Table "public.testpub_tbl_both_filters" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | (primary key) | | plain | | + b | integer | | | | plain | | + c | integer | | (primary key) | | plain | | Indexes: "testpub_tbl_both_filters_pkey" PRIMARY KEY, btree (a, c) REPLICA IDENTITY Publications: @@ -1116,22 +1116,22 @@ ALTER PUBLICATION testpub_default SET TABLE testpub_tbl1; ALTER PUBLICATION testpub_default ADD TABLE pub_test.testpub_nopk; ALTER PUBLICATION testpib_ins_trunct ADD TABLE pub_test.testpub_nopk, testpub_tbl1; \d+ pub_test.testpub_nopk - Table "pub_test.testpub_nopk" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - foo | integer | | | | plain | | - bar | integer | | | | plain | | + Table "pub_test.testpub_nopk" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + foo | integer | | | | plain | | + bar | integer | | | | plain | | Publications: "testpib_ins_trunct" "testpub_default" "testpub_fortbl" \d+ testpub_tbl1 - Table "public.testpub_tbl1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('testpub_tbl1_id_seq'::regclass) | plain | | - data | text | | | | extended | | + Table "public.testpub_tbl1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+--------------------------+------------------------------------------+----------+--------------+------------- + id | integer | | testpub_tbl1_id_not_null | nextval('testpub_tbl1_id_seq'::regclass) | plain | | + data | text | | | | extended | | Indexes: "testpub_tbl1_pkey" PRIMARY KEY, btree (id) Publications: @@ -1153,11 +1153,11 @@ ALTER PUBLICATION testpub_default DROP TABLE testpub_tbl1, pub_test.testpub_nopk ALTER PUBLICATION testpub_default DROP TABLE pub_test.testpub_nopk; ERROR: relation "testpub_nopk" is not part of the publication \d+ testpub_tbl1 - Table "public.testpub_tbl1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('testpub_tbl1_id_seq'::regclass) | plain | | - data | text | | | | extended | | + Table "public.testpub_tbl1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+--------------------------+------------------------------------------+----------+--------------+------------- + id | integer | | testpub_tbl1_id_not_null | nextval('testpub_tbl1_id_seq'::regclass) | plain | | + data | text | | | | extended | | Indexes: "testpub_tbl1_pkey" PRIMARY KEY, btree (id) Publications: diff --git a/src/test/regress/expected/replica_identity.out b/src/test/regress/expected/replica_identity.out index 9571840d25..f1f2afd9be 100644 --- a/src/test/regress/expected/replica_identity.out +++ b/src/test/regress/expected/replica_identity.out @@ -153,13 +153,13 @@ SELECT relreplident FROM pg_class WHERE oid = 'test_replica_identity'::regclass; (1 row) \d+ test_replica_identity - Table "public.test_replica_identity" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------------------------------------------------+----------+--------------+------------- - id | integer | | not null | nextval('test_replica_identity_id_seq'::regclass) | plain | | - keya | text | | not null | | extended | | - keyb | text | | not null | | extended | | - nonkey | text | | | | extended | | + Table "public.test_replica_identity" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+-------------------------------------+---------------------------------------------------+----------+--------------+------------- + id | integer | | test_replica_identity_id_not_null | nextval('test_replica_identity_id_seq'::regclass) | plain | | + keya | text | | test_replica_identity_keya_not_null | | extended | | + keyb | text | | test_replica_identity_keyb_not_null | | extended | | + nonkey | text | | | | extended | | Indexes: "test_replica_identity_pkey" PRIMARY KEY, btree (id) "test_replica_identity_expr" UNIQUE, btree (keya, keyb, (3)) @@ -242,10 +242,10 @@ ALTER TABLE ONLY test_replica_identity4 ALTER TABLE ONLY test_replica_identity4_1 ADD CONSTRAINT test_replica_identity4_1_pkey PRIMARY KEY (id); \d+ test_replica_identity4 - Partitioned table "public.test_replica_identity4" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - id | integer | | not null | | plain | | + Partitioned table "public.test_replica_identity4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+------------------------------------+---------+---------+--------------+------------- + id | integer | | test_replica_identity4_id_not_null | | plain | | Partition key: LIST (id) Indexes: "test_replica_identity4_pkey" PRIMARY KEY, btree (id) INVALID REPLICA IDENTITY @@ -254,10 +254,10 @@ Partitions: test_replica_identity4_1 FOR VALUES IN (1) ALTER INDEX test_replica_identity4_pkey ATTACH PARTITION test_replica_identity4_1_pkey; \d+ test_replica_identity4 - Partitioned table "public.test_replica_identity4" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - id | integer | | not null | | plain | | + Partitioned table "public.test_replica_identity4" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+------------------------------------+---------+---------+--------------+------------- + id | integer | | test_replica_identity4_id_not_null | | plain | | Partition key: LIST (id) Indexes: "test_replica_identity4_pkey" PRIMARY KEY, btree (id) REPLICA IDENTITY diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out index a415ad168c..6e9dcfb419 100644 --- a/src/test/regress/expected/rowsecurity.out +++ b/src/test/regress/expected/rowsecurity.out @@ -938,14 +938,14 @@ CREATE POLICY pp1 ON part_document AS PERMISSIVE CREATE POLICY pp1r ON part_document AS RESTRICTIVE TO regress_rls_dave USING (cid < 55); \d+ part_document - Partitioned table "regress_rls_schema.part_document" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ----------+---------+-----------+----------+---------+----------+--------------+------------- - did | integer | | | | plain | | - cid | integer | | | | plain | | - dlevel | integer | | not null | | plain | | - dauthor | name | | | | plain | | - dtitle | text | | | | extended | | + Partitioned table "regress_rls_schema.part_document" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +---------+---------+-----------+-------------------------------+---------+----------+--------------+------------- + did | integer | | | | plain | | + cid | integer | | | | plain | | + dlevel | integer | | part_document_dlevel_not_null | | plain | | + dauthor | name | | | | plain | | + dtitle | text | | | | extended | | Partition key: RANGE (cid) Policies: POLICY "pp1" diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index e953d1f515..610e88cdf0 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -3014,11 +3014,11 @@ create rule r7 as on delete to rules_src do instead returning trgt.f1, trgt.f2; -- check display of all rules added above \d+ rules_src - Table "public.rules_src" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - f1 | integer | | | | plain | | - f2 | integer | | | 0 | plain | | + Table "public.rules_src" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + f1 | integer | | | | plain | | + f2 | integer | | | 0 | plain | | Rules: r1 AS ON UPDATE TO rules_src DO INSERT INTO rules_log (f1, f2, tag, id) VALUES (old.f1,old.f2,'old'::text,DEFAULT), (new.f1,new.f2,'new'::text,DEFAULT) @@ -3067,11 +3067,11 @@ create rule rr as on update to rule_t1 do instead UPDATE rule_dest trgt SET (f2[1], f1, tag) = (SELECT new.f2, new.f1, 'updated'::varchar) WHERE trgt.f1 = new.f1 RETURNING new.*; \d+ rule_t1 - Table "public.rule_t1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - f1 | integer | | | | plain | | - f2 | integer | | | | plain | | + Table "public.rule_t1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + f1 | integer | | | | plain | | + f2 | integer | | | | plain | | Rules: rr AS ON UPDATE TO rule_t1 DO INSTEAD UPDATE rule_dest trgt SET (f2[1], f1, tag) = ( SELECT new.f2, @@ -3125,10 +3125,10 @@ SELECT * FROM rule_v1; (1 row) \d+ rule_v1 - View "public.rule_v1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | + View "public.rule_v1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | View definition: SELECT a FROM rule_t1; @@ -3153,21 +3153,21 @@ DROP TABLE rule_t1; -- create view rule_v1 as values(1,2); \d+ rule_v1 - View "public.rule_v1" - Column | Type | Collation | Nullable | Default | Storage | Description ----------+---------+-----------+----------+---------+---------+------------- - column1 | integer | | | | plain | - column2 | integer | | | | plain | + View "public.rule_v1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +---------+---------+-----------+---------------------+---------+---------+------------- + column1 | integer | | | | plain | + column2 | integer | | | | plain | View definition: VALUES (1,2); alter table rule_v1 rename column column2 to q2; \d+ rule_v1 - View "public.rule_v1" - Column | Type | Collation | Nullable | Default | Storage | Description ----------+---------+-----------+----------+---------+---------+------------- - column1 | integer | | | | plain | - q2 | integer | | | | plain | + View "public.rule_v1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +---------+---------+-----------+---------------------+---------+---------+------------- + column1 | integer | | | | plain | + q2 | integer | | | | plain | View definition: SELECT column1, column2 AS q2 @@ -3176,11 +3176,11 @@ View definition: drop view rule_v1; create view rule_v1(x) as values(1,2); \d+ rule_v1 - View "public.rule_v1" - Column | Type | Collation | Nullable | Default | Storage | Description ----------+---------+-----------+----------+---------+---------+------------- - x | integer | | | | plain | - column2 | integer | | | | plain | + View "public.rule_v1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +---------+---------+-----------+---------------------+---------+---------+------------- + x | integer | | | | plain | + column2 | integer | | | | plain | View definition: SELECT column1 AS x, column2 @@ -3189,11 +3189,11 @@ View definition: drop view rule_v1; create view rule_v1(x) as select * from (values(1,2)) v; \d+ rule_v1 - View "public.rule_v1" - Column | Type | Collation | Nullable | Default | Storage | Description ----------+---------+-----------+----------+---------+---------+------------- - x | integer | | | | plain | - column2 | integer | | | | plain | + View "public.rule_v1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +---------+---------+-----------+---------------------+---------+---------+------------- + x | integer | | | | plain | + column2 | integer | | | | plain | View definition: SELECT column1 AS x, column2 @@ -3202,11 +3202,11 @@ View definition: drop view rule_v1; create view rule_v1(x) as select * from (values(1,2)) v(q,w); \d+ rule_v1 - View "public.rule_v1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - x | integer | | | | plain | - w | integer | | | | plain | + View "public.rule_v1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + x | integer | | | | plain | + w | integer | | | | plain | View definition: SELECT q AS x, w diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out index 03880874c1..e5e088ae26 100644 --- a/src/test/regress/expected/stats_ext.out +++ b/src/test/regress/expected/stats_ext.out @@ -150,11 +150,11 @@ SELECT stxname, stxdndistinct, stxddependencies, stxdmcv, stxdinherit ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1; \d+ ab1 - Table "public.ab1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | - b | integer | | | | plain | | + Table "public.ab1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | + b | integer | | | | plain | | Statistics objects: "public.ab1_a_b_stats" ON a, b FROM ab1 diff --git a/src/test/regress/expected/tablesample.out b/src/test/regress/expected/tablesample.out index 9ff4611640..2c6defc350 100644 --- a/src/test/regress/expected/tablesample.out +++ b/src/test/regress/expected/tablesample.out @@ -69,19 +69,19 @@ CREATE VIEW test_tablesample_v1 AS CREATE VIEW test_tablesample_v2 AS SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (99); \d+ test_tablesample_v1 - View "public.test_tablesample_v1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - id | integer | | | | plain | + View "public.test_tablesample_v1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + id | integer | | | | plain | View definition: SELECT id FROM test_tablesample TABLESAMPLE system ((10 * 2)) REPEATABLE (2); \d+ test_tablesample_v2 - View "public.test_tablesample_v2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - id | integer | | | | plain | + View "public.test_tablesample_v2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + id | integer | | | | plain | View definition: SELECT id FROM test_tablesample TABLESAMPLE system (99); diff --git a/src/test/regress/expected/tablespace.out b/src/test/regress/expected/tablespace.out index 9aabb85349..62dff66e68 100644 --- a/src/test/regress/expected/tablespace.out +++ b/src/test/regress/expected/tablespace.out @@ -348,10 +348,10 @@ Indexes: Number of partitions: 2 (Use \d+ to list them.) \d+ testschema.part - Partitioned table "testschema.part" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | + Partitioned table "testschema.part" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | Partition key: LIST (a) Indexes: "part_a_idx" btree (a), tablespace "regress_tblspace" @@ -368,10 +368,10 @@ Indexes: "part1_a_idx" btree (a), tablespace "regress_tblspace" \d+ testschema.part1 - Table "testschema.part1" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | + Table "testschema.part1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | Partition of: testschema.part FOR VALUES IN (1) Partition constraint: ((a IS NOT NULL) AND (a = 1)) Indexes: diff --git a/src/test/regress/expected/triggers.out b/src/test/regress/expected/triggers.out index 7dbeced570..0a41c01527 100644 --- a/src/test/regress/expected/triggers.out +++ b/src/test/regress/expected/triggers.out @@ -1271,11 +1271,11 @@ Triggers: DROP TRIGGER instead_of_insert_trig ON main_view; DROP TRIGGER instead_of_delete_trig ON main_view; \d+ main_view - View "public.main_view" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | - b | integer | | | | plain | + View "public.main_view" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | + b | integer | | | | plain | View definition: SELECT a, b @@ -3608,10 +3608,10 @@ create trigger parenttrig after insert on child for each row execute procedure f(); alter trigger parenttrig on parent rename to anothertrig; \d+ child - Table "public.child" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+---------+-----------+----------+---------+---------+--------------+------------- - a | integer | | | | plain | | + Table "public.child" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+---------+-----------+---------------------+---------+---------+--------------+------------- + a | integer | | | | plain | | Triggers: parenttrig AFTER INSERT ON child FOR EACH ROW EXECUTE FUNCTION f() Inherits: parent diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out index 0cbedc657d..587d455787 100644 --- a/src/test/regress/expected/updatable_views.out +++ b/src/test/regress/expected/updatable_views.out @@ -1919,11 +1919,11 @@ INSERT INTO base_tbl VALUES (1,2), (2,3), (1,-1); CREATE VIEW rw_view1 AS SELECT * FROM base_tbl WHERE a < b WITH LOCAL CHECK OPTION; \d+ rw_view1 - View "public.rw_view1" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | - b | integer | | | | plain | + View "public.rw_view1" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | + b | integer | | | | plain | View definition: SELECT a, b @@ -1973,10 +1973,10 @@ CREATE VIEW rw_view1 AS SELECT * FROM base_tbl WHERE a > 0; CREATE VIEW rw_view2 AS SELECT * FROM rw_view1 WHERE a < 10 WITH CHECK OPTION; -- implicitly cascaded \d+ rw_view2 - View "public.rw_view2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | + View "public.rw_view2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | View definition: SELECT a FROM rw_view1 @@ -2013,10 +2013,10 @@ DETAIL: Failing row contains (15). CREATE OR REPLACE VIEW rw_view2 AS SELECT * FROM rw_view1 WHERE a < 10 WITH LOCAL CHECK OPTION; \d+ rw_view2 - View "public.rw_view2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | + View "public.rw_view2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | View definition: SELECT a FROM rw_view1 @@ -2054,10 +2054,10 @@ ERROR: new row violates check option for view "rw_view2" DETAIL: Failing row contains (30). ALTER VIEW rw_view2 RESET (check_option); \d+ rw_view2 - View "public.rw_view2" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+---------+-----------+----------+---------+---------+------------- - a | integer | | | | plain | + View "public.rw_view2" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+---------+-----------+---------------------+---------+---------+------------- + a | integer | | | | plain | View definition: SELECT a FROM rw_view1 diff --git a/src/test/regress/expected/update.out b/src/test/regress/expected/update.out index c809f88f54..3ef07f466b 100644 --- a/src/test/regress/expected/update.out +++ b/src/test/regress/expected/update.out @@ -743,14 +743,14 @@ DROP TRIGGER d15_insert_trig ON part_d_15_20; :init_range_parted; create table part_def partition of range_parted default; \d+ part_def - Table "public.part_def" - Column | Type | Collation | Nullable | Default | Storage | Stats target | Description ---------+-------------------+-----------+----------+---------+----------+--------------+------------- - a | text | | | | extended | | - b | bigint | | | | plain | | - c | numeric | | | | main | | - d | integer | | | | plain | | - e | character varying | | | | extended | | + Table "public.part_def" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Stats target | Description +--------+-------------------+-----------+---------------------+---------+----------+--------------+------------- + a | text | | | | extended | | + b | bigint | | | | plain | | + c | numeric | | | | main | | + d | integer | | | | plain | | + e | character varying | | | | extended | | Partition of: range_parted DEFAULT Partition constraint: (NOT ((a IS NOT NULL) AND (b IS NOT NULL) AND (((a = 'a'::text) AND (b >= '1'::bigint) AND (b < '10'::bigint)) OR ((a = 'a'::text) AND (b >= '10'::bigint) AND (b < '20'::bigint)) OR ((a = 'b'::text) AND (b >= '1'::bigint) AND (b < '10'::bigint)) OR ((a = 'b'::text) AND (b >= '10'::bigint) AND (b < '20'::bigint)) OR ((a = 'b'::text) AND (b >= '20'::bigint) AND (b < '30'::bigint))))) diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out index 88e57a2c87..c00e40e7db 100644 --- a/src/test/regress/expected/with.out +++ b/src/test/regress/expected/with.out @@ -434,10 +434,10 @@ UNION ALL ) SELECT sum(n) FROM t; \d+ sums_1_100 - View "public.sums_1_100" - Column | Type | Collation | Nullable | Default | Storage | Description ---------+--------+-----------+----------+---------+---------+------------- - sum | bigint | | | | plain | + View "public.sums_1_100" + Column | Type | Collation | NOT NULL Constraint | Default | Storage | Description +--------+--------+-----------+---------------------+---------+---------+------------- + sum | bigint | | | | plain | View definition: WITH RECURSIVE t(n) AS ( VALUES (1) -- 2.30.2 --kprtg3rp4osk374p-- ^ permalink raw reply [nested|flat] 228+ messages in thread
end of thread, other threads:[~2023-02-24 11:02 UTC | newest] Thread overview: 228+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v57 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v30 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v57 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v41 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v36 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v35 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v37 5/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v39 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v25 7/8] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v33 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v32 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v33 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v44 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v38 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v31 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v29 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v40 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v42 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v45 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v34 6/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v47 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v43 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v51 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v56 4/6] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v48 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v46 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v50 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2020-03-19 06:11 [PATCH v52 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]> 2023-02-24 11:02 [PATCH v4 3/3] have psql \d+ show the constraint name Alvaro Herrera <[email protected]>
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