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* [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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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
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filename="v47-0006-Remove-the-GUC-stats_temp_directory.patch"
^ permalink raw reply [nested|flat] 233+ 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; 233+ 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
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Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v48-0006-Remove-the-GUC-stats_temp_directory.patch"
^ permalink raw reply [nested|flat] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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)--
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Content-Transfer-Encoding: 7bit
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filename="v51-0006-Remove-the-GUC-stats_temp_directory.patch"
^ permalink raw reply [nested|flat] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ 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; 233+ 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] 233+ messages in thread
* BufferUsage counters' values have changed
@ 2023-09-11 06:08 Karina Litskevich <[email protected]>
0 siblings, 2 replies; 233+ messages in thread
From: Karina Litskevich @ 2023-09-11 06:08 UTC (permalink / raw)
To: pgsql-hackers
Hi hackers,
I noticed that BufferUsage counters' values are strangely different for the
same queries on REL_15_STABLE and REL_16_STABLE. For example, I run
CREATE EXTENSION pg_stat_statements;
CREATE TEMP TABLE test(b int);
INSERT INTO test(b) SELECT generate_series(1,1000);
SELECT query, local_blks_hit, local_blks_read, local_blks_written,
local_blks_dirtied, temp_blks_written FROM pg_stat_statements;
and output on REL_15_STABLE contains
query | INSERT INTO test(b) SELECT generate_series($1,$2)
local_blks_hit | 1005
local_blks_read | 2
local_blks_written | 5
local_blks_dirtied | 5
temp_blks_written | 0
while output on REL_16_STABLE contains
query | INSERT INTO test(b) SELECT generate_series($1,$2)
local_blks_hit | 1006
local_blks_read | 0
local_blks_written | 0
local_blks_dirtied | 5
temp_blks_written | 8
I found a bug that causes one of the differences. Wrong counter is
incremented
in ExtendBufferedRelLocal(). The attached patch fixes it and should be
applied
to REL_16_STABLE and master. With the patch applied output contains
query | INSERT INTO test(b) SELECT generate_series($1,$2)
local_blks_hit | 1006
local_blks_read | 0
local_blks_written | 8
local_blks_dirtied | 5
temp_blks_written | 0
I still wonder why local_blks_written is greater than it was on
REL_15_STABLE,
and why local_blks_read became zero. These changes are caused by fcdda1e4b5.
This code is new to me, and I'm still trying to understand whether it's a
bug
in computing the counters or just changes in how many blocks are
read/written
during the query execution. If anyone can help me, I would be grateful.
Best regards,
Karina Litskevich
Postgres Professional: http://postgrespro.com/
^ permalink raw reply [nested|flat] 233+ messages in thread
* Re: BufferUsage counters' values have changed
@ 2023-09-11 06:23 Karina Litskevich <[email protected]>
parent: Karina Litskevich <[email protected]>
1 sibling, 1 reply; 233+ messages in thread
From: Karina Litskevich @ 2023-09-11 06:23 UTC (permalink / raw)
To: pgsql-hackers
On Mon, Sep 11, 2023 at 9:08 AM Karina Litskevich <
[email protected]> wrote:
> I found a bug that causes one of the differences. Wrong counter is
> incremented
> in ExtendBufferedRelLocal(). The attached patch fixes it and should be
> applied
> to REL_16_STABLE and master.
>
I've forgotten to attach the patch. Here it is.
Attachments:
[text/x-patch] v1-0001-Fix-local_blks_written-counter-incrementation.patch (779B, ../../CACiT8iZvy5W8DzEd3WJimhxK-9==gLhUjotZ+Ooun3Vs3UCT6w@mail.gmail.com/3-v1-0001-Fix-local_blks_written-counter-incrementation.patch)
download | inline diff:
From 999a3d533a9b74c8568cc8a3d715c287de45dd2c Mon Sep 17 00:00:00 2001
From: Karina Litskevich <[email protected]>
Date: Thu, 7 Sep 2023 17:44:40 +0300
Subject: [PATCH v1] Fix local_blks_written counter incrementation
---
src/backend/storage/buffer/localbuf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 1735ec7141..567b8d15ef 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -431,7 +431,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
*extended_by = extend_by;
- pgBufferUsage.temp_blks_written += extend_by;
+ pgBufferUsage.local_blks_written += extend_by;
return first_block;
}
--
2.34.1
^ permalink raw reply [nested|flat] 233+ messages in thread
* Re: BufferUsage counters' values have changed
@ 2023-09-13 13:04 Nazir Bilal Yavuz <[email protected]>
parent: Karina Litskevich <[email protected]>
1 sibling, 1 reply; 233+ messages in thread
From: Nazir Bilal Yavuz @ 2023-09-13 13:04 UTC (permalink / raw)
To: Karina Litskevich <[email protected]>; +Cc: pgsql-hackers
Hi,
On Mon, 11 Sept 2023 at 14:28, Karina Litskevich
<[email protected]> wrote:
>
> Hi hackers,
>
> I noticed that BufferUsage counters' values are strangely different for the
> same queries on REL_15_STABLE and REL_16_STABLE. For example, I run
>
> CREATE EXTENSION pg_stat_statements;
> CREATE TEMP TABLE test(b int);
> INSERT INTO test(b) SELECT generate_series(1,1000);
> SELECT query, local_blks_hit, local_blks_read, local_blks_written,
> local_blks_dirtied, temp_blks_written FROM pg_stat_statements;
>
> and output on REL_15_STABLE contains
>
> query | INSERT INTO test(b) SELECT generate_series($1,$2)
> local_blks_hit | 1005
> local_blks_read | 2
> local_blks_written | 5
> local_blks_dirtied | 5
> temp_blks_written | 0
>
> while output on REL_16_STABLE contains
>
> query | INSERT INTO test(b) SELECT generate_series($1,$2)
> local_blks_hit | 1006
> local_blks_read | 0
> local_blks_written | 0
> local_blks_dirtied | 5
> temp_blks_written | 8
>
>
> I found a bug that causes one of the differences. Wrong counter is incremented
> in ExtendBufferedRelLocal(). The attached patch fixes it and should be applied
> to REL_16_STABLE and master. With the patch applied output contains
Nice finding! I agree, it should be changed.
> query | INSERT INTO test(b) SELECT generate_series($1,$2)
> local_blks_hit | 1006
> local_blks_read | 0
> local_blks_written | 8
> local_blks_dirtied | 5
> temp_blks_written | 0
>
>
> I still wonder why local_blks_written is greater than it was on REL_15_STABLE,
> and why local_blks_read became zero. These changes are caused by fcdda1e4b5.
> This code is new to me, and I'm still trying to understand whether it's a bug
> in computing the counters or just changes in how many blocks are read/written
> during the query execution. If anyone can help me, I would be grateful.
I spent some time on it:
local_blks_read became zero because:
1_ One more cache hit. It was supposed to be local_blks_read but it is
local_blks_hit now. This is an assumption, I didn't check this deeply.
2_ Before fcdda1e4b5, there was one local_blks_read coming from
buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
RBM_ZERO_ON_ERROR, NULL) in freespace.c -> ReadBuffer_common() ->
pgBufferUsage.local_blks_read++.
But buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
RBM_ZERO_ON_ERROR, NULL) is moved into the else case, so it didn't
called and local_blks_read isn't incremented.
local_blks_written is greater because of the combination of fcdda1e4b5
and 00d1e02be2.
In PG_15:
RelationGetBufferForTuple() -> ReadBufferBI(P_NEW, RBM_ZERO_AND_LOCK)
-> ReadBufferExtended() -> ReadBuffer_common() ->
pgBufferUsage.local_blks_written++; (called 5 times) [0]
In PG_16:
1_ 5 of the local_blks_written is coming from:
RelationGetBufferForTuple() -> RelationAddBlocks() ->
ExtendBufferedRelBy() -> ExtendBufferedRelCommon() ->
ExtendBufferedRelLocal() -> pgBufferUsage.local_blks_written +=
extend_by; (extend_by is 1, this is called 5 times) [1]
2_ 3 of the local_blks_written is coming from:
RelationGetBufferForTuple() -> RecordAndGetPageWithFreeSpace() ->
fsm_set_and_search() -> fsm_readbuf() -> fsm_extend() ->
ExtendBufferedRelTo() -> ExtendBufferedRelCommon() ->
ExtendBufferedRelLocal() -> pgBufferUsage.local_blks_written +=
extend_by; (extend_by is 3, this is called 1 time) [2]
I think [0] is the same path as [1] but [2] is new. 'fsm extends'
wasn't counted in local_blks_written in PG_15. Calling
ExtendBufferedRelTo() from fsm_extend() caused 'fsm extends' to be
counted in local_blks_written. I am not sure which one is correct.
I hope these help.
Regards,
Nazir Bilal Yavuz
Microsoft
^ permalink raw reply [nested|flat] 233+ messages in thread
* Re: BufferUsage counters' values have changed
@ 2023-09-13 18:59 Andres Freund <[email protected]>
parent: Karina Litskevich <[email protected]>
0 siblings, 0 replies; 233+ messages in thread
From: Andres Freund @ 2023-09-13 18:59 UTC (permalink / raw)
To: Karina Litskevich <[email protected]>; +Cc: pgsql-hackers; Nazir Bilal Yavuz <[email protected]>
Hi,
On 2023-09-11 09:23:59 +0300, Karina Litskevich wrote:
> On Mon, Sep 11, 2023 at 9:08 AM Karina Litskevich <
> [email protected]> wrote:
>
> > I found a bug that causes one of the differences. Wrong counter is
> > incremented
> > in ExtendBufferedRelLocal(). The attached patch fixes it and should be
> > applied
> > to REL_16_STABLE and master.
> >
>
> I've forgotten to attach the patch. Here it is.
> From 999a3d533a9b74c8568cc8a3d715c287de45dd2c Mon Sep 17 00:00:00 2001
> From: Karina Litskevich <[email protected]>
> Date: Thu, 7 Sep 2023 17:44:40 +0300
> Subject: [PATCH v1] Fix local_blks_written counter incrementation
>
> ---
> src/backend/storage/buffer/localbuf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
> index 1735ec7141..567b8d15ef 100644
> --- a/src/backend/storage/buffer/localbuf.c
> +++ b/src/backend/storage/buffer/localbuf.c
> @@ -431,7 +431,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
>
> *extended_by = extend_by;
>
> - pgBufferUsage.temp_blks_written += extend_by;
> + pgBufferUsage.local_blks_written += extend_by;
>
> return first_block;
> }
> --
> 2.34.1
>
Ugh, you're right.
The naming of local vs temp here is pretty unfortunate imo. I wonder if we
ought to at least dd a comment to BufferUsage clarifying the situation? Just
reading the comments therein one would be hard pressed to figure out which of
the variables temp table activity should be added to.
I don't think we currently can write a test for this in the core tests, as the
relevant data isn't visible anywhere, iirc. Thus I added a test to
pg_stat_statements. Afaict it should be stable?
Running the attached patch through CI, planning to push after that succeeds,
unless somebody has a comment?
Greetings,
Andres Freund
Attachments:
[text/x-diff] v2-0001-Fix-tracking-of-temp-table-relation-extensions-as.patch (4.6K, ../../[email protected]/2-v2-0001-Fix-tracking-of-temp-table-relation-extensions-as.patch)
download | inline diff:
From ae7b170e9032af0fd257a39953fe0b6ef7e9637c Mon Sep 17 00:00:00 2001
From: Andres Freund <[email protected]>
Date: Wed, 13 Sep 2023 11:46:45 -0700
Subject: [PATCH v2] Fix tracking of temp table relation extensions as writes
Karina figured out that I (Andres) confused BufferUsage.temp_blks_written with
BufferUsage.local_blks_written in fcdda1e4b5.
Tests in core PG can't easily test this, as BufferUsage is just used for
EXPLAIN (ANALYZE, BUFFERS) and pg_stat_statements. Thus this commit adds tests
for this to pg_stat_statements.
Reported-by: Karina Litskevich <[email protected]>
Author: Karina Litskevich <[email protected]>
Author: Andres Freund <[email protected]>
Discussion: https://postgr.es/m/CACiT8ibxXA6+0amGikbeFhm8B84XdQVo6D0Qfd1pQ1s8zpsnxQ@mail.gmail.com
Backpatch: 16-, where fcdda1e4b5 was merged
---
src/backend/storage/buffer/localbuf.c | 2 +-
contrib/pg_stat_statements/expected/dml.out | 27 +++++++++++++++++++++
contrib/pg_stat_statements/sql/dml.sql | 19 +++++++++++++++
3 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 1735ec71419..567b8d15ef0 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -431,7 +431,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
*extended_by = extend_by;
- pgBufferUsage.temp_blks_written += extend_by;
+ pgBufferUsage.local_blks_written += extend_by;
return first_block;
}
diff --git a/contrib/pg_stat_statements/expected/dml.out b/contrib/pg_stat_statements/expected/dml.out
index 7b9c8f979ee..ede47a71acc 100644
--- a/contrib/pg_stat_statements/expected/dml.out
+++ b/contrib/pg_stat_statements/expected/dml.out
@@ -139,6 +139,33 @@ SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
1 | 1 | SELECT pg_stat_statements_reset()
(10 rows)
+-- check that [temp] table relation extensions are tracked as writes
+CREATE TABLE pgss_extend_tab (a int, b text);
+CREATE TEMP TABLE pgss_extend_temp_tab (a int, b text);
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+INSERT INTO pgss_extend_tab (a, b) SELECT generate_series(1, 1000), 'something';
+INSERT INTO pgss_extend_temp_tab (a, b) SELECT generate_series(1, 1000), 'something';
+WITH sizes AS (
+ SELECT
+ pg_relation_size('pgss_extend_tab') / current_setting('block_size')::int8 AS rel_size,
+ pg_relation_size('pgss_extend_temp_tab') / current_setting('block_size')::int8 AS temp_rel_size
+)
+SELECT
+ SUM(local_blks_written) >= (SELECT temp_rel_size FROM sizes) AS temp_written_ok,
+ SUM(local_blks_dirtied) >= (SELECT temp_rel_size FROM sizes) AS temp_dirtied_ok,
+ SUM(shared_blks_written) >= (SELECT rel_size FROM sizes) AS written_ok,
+ SUM(shared_blks_dirtied) >= (SELECT rel_size FROM sizes) AS dirtied_ok
+FROM pg_stat_statements;
+ temp_written_ok | temp_dirtied_ok | written_ok | dirtied_ok
+-----------------+-----------------+------------+------------
+ t | t | t | t
+(1 row)
+
SELECT pg_stat_statements_reset();
pg_stat_statements_reset
--------------------------
diff --git a/contrib/pg_stat_statements/sql/dml.sql b/contrib/pg_stat_statements/sql/dml.sql
index af2f9fcf73b..3b5d2afb858 100644
--- a/contrib/pg_stat_statements/sql/dml.sql
+++ b/contrib/pg_stat_statements/sql/dml.sql
@@ -73,4 +73,23 @@ MERGE INTO pgss_dml_tab USING pgss_dml_tab st ON (st.a = pgss_dml_tab.a AND st.a
DROP TABLE pgss_dml_tab;
SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- check that [temp] table relation extensions are tracked as writes
+CREATE TABLE pgss_extend_tab (a int, b text);
+CREATE TEMP TABLE pgss_extend_temp_tab (a int, b text);
+SELECT pg_stat_statements_reset();
+INSERT INTO pgss_extend_tab (a, b) SELECT generate_series(1, 1000), 'something';
+INSERT INTO pgss_extend_temp_tab (a, b) SELECT generate_series(1, 1000), 'something';
+WITH sizes AS (
+ SELECT
+ pg_relation_size('pgss_extend_tab') / current_setting('block_size')::int8 AS rel_size,
+ pg_relation_size('pgss_extend_temp_tab') / current_setting('block_size')::int8 AS temp_rel_size
+)
+SELECT
+ SUM(local_blks_written) >= (SELECT temp_rel_size FROM sizes) AS temp_written_ok,
+ SUM(local_blks_dirtied) >= (SELECT temp_rel_size FROM sizes) AS temp_dirtied_ok,
+ SUM(shared_blks_written) >= (SELECT rel_size FROM sizes) AS written_ok,
+ SUM(shared_blks_dirtied) >= (SELECT rel_size FROM sizes) AS dirtied_ok
+FROM pg_stat_statements;
+
SELECT pg_stat_statements_reset();
--
2.38.0
^ permalink raw reply [nested|flat] 233+ messages in thread
* Re: BufferUsage counters' values have changed
@ 2023-09-13 19:10 Andres Freund <[email protected]>
parent: Nazir Bilal Yavuz <[email protected]>
0 siblings, 1 reply; 233+ messages in thread
From: Andres Freund @ 2023-09-13 19:10 UTC (permalink / raw)
To: Nazir Bilal Yavuz <[email protected]>; +Cc: Karina Litskevich <[email protected]>; pgsql-hackers
Hi,
On 2023-09-13 16:04:00 +0300, Nazir Bilal Yavuz wrote:
> On Mon, 11 Sept 2023 at 14:28, Karina Litskevich
> <[email protected]> wrote:
> >
> > Hi hackers,
> >
> > I noticed that BufferUsage counters' values are strangely different for the
> > same queries on REL_15_STABLE and REL_16_STABLE. For example, I run
> >
> > CREATE EXTENSION pg_stat_statements;
> > CREATE TEMP TABLE test(b int);
> > INSERT INTO test(b) SELECT generate_series(1,1000);
> > SELECT query, local_blks_hit, local_blks_read, local_blks_written,
> > local_blks_dirtied, temp_blks_written FROM pg_stat_statements;
> >
> > and output on REL_15_STABLE contains
> >
> > query | INSERT INTO test(b) SELECT generate_series($1,$2)
> > local_blks_hit | 1005
> > local_blks_read | 2
> > local_blks_written | 5
> > local_blks_dirtied | 5
> > temp_blks_written | 0
> >
> > while output on REL_16_STABLE contains
> >
> > query | INSERT INTO test(b) SELECT generate_series($1,$2)
> > local_blks_hit | 1006
> > local_blks_read | 0
> > local_blks_written | 0
> > local_blks_dirtied | 5
> > temp_blks_written | 8
> >
> >
> > I found a bug that causes one of the differences. Wrong counter is incremented
> > in ExtendBufferedRelLocal(). The attached patch fixes it and should be applied
> > to REL_16_STABLE and master. With the patch applied output contains
>
> Nice finding! I agree, it should be changed.
>
> > query | INSERT INTO test(b) SELECT generate_series($1,$2)
> > local_blks_hit | 1006
> > local_blks_read | 0
> > local_blks_written | 8
> > local_blks_dirtied | 5
> > temp_blks_written | 0
> >
> >
> > I still wonder why local_blks_written is greater than it was on REL_15_STABLE,
> > and why local_blks_read became zero. These changes are caused by fcdda1e4b5.
> > This code is new to me, and I'm still trying to understand whether it's a bug
> > in computing the counters or just changes in how many blocks are read/written
> > during the query execution. If anyone can help me, I would be grateful.
>
> I spent some time on it:
>
> local_blks_read became zero because:
> 1_ One more cache hit. It was supposed to be local_blks_read but it is
> local_blks_hit now. This is an assumption, I didn't check this deeply.
> 2_ Before fcdda1e4b5, there was one local_blks_read coming from
> buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
> RBM_ZERO_ON_ERROR, NULL) in freespace.c -> ReadBuffer_common() ->
> pgBufferUsage.local_blks_read++.
> But buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
> RBM_ZERO_ON_ERROR, NULL) is moved into the else case, so it didn't
> called and local_blks_read isn't incremented.
That imo is a legitimate difference / improvement. The read we previously did
here was unnecessary.
> local_blks_written is greater because of the combination of fcdda1e4b5
> and 00d1e02be2.
> In PG_15:
> RelationGetBufferForTuple() -> ReadBufferBI(P_NEW, RBM_ZERO_AND_LOCK)
> -> ReadBufferExtended() -> ReadBuffer_common() ->
> pgBufferUsage.local_blks_written++; (called 5 times) [0]
> In PG_16:
> 1_ 5 of the local_blks_written is coming from:
> RelationGetBufferForTuple() -> RelationAddBlocks() ->
> ExtendBufferedRelBy() -> ExtendBufferedRelCommon() ->
> ExtendBufferedRelLocal() -> pgBufferUsage.local_blks_written +=
> extend_by; (extend_by is 1, this is called 5 times) [1]
> 2_ 3 of the local_blks_written is coming from:
> RelationGetBufferForTuple() -> RecordAndGetPageWithFreeSpace() ->
> fsm_set_and_search() -> fsm_readbuf() -> fsm_extend() ->
> ExtendBufferedRelTo() -> ExtendBufferedRelCommon() ->
> ExtendBufferedRelLocal() -> pgBufferUsage.local_blks_written +=
> extend_by; (extend_by is 3, this is called 1 time) [2]
>
> I think [0] is the same path as [1] but [2] is new. 'fsm extends'
> wasn't counted in local_blks_written in PG_15. Calling
> ExtendBufferedRelTo() from fsm_extend() caused 'fsm extends' to be
> counted in local_blks_written. I am not sure which one is correct.
I think it's correct to count the fsm writes here. The pg_stat_statement
columns aren't specific to the main relation for or such... If anything it was
a bug to not count them before.
Thanks for looking into this.
Greetings,
Andres Freund
^ permalink raw reply [nested|flat] 233+ messages in thread
* Re: BufferUsage counters' values have changed
@ 2023-09-15 07:37 Karina Litskevich <[email protected]>
parent: Andres Freund <[email protected]>
0 siblings, 0 replies; 233+ messages in thread
From: Karina Litskevich @ 2023-09-15 07:37 UTC (permalink / raw)
To: Andres Freund <[email protected]>; +Cc: Nazir Bilal Yavuz <[email protected]>; pgsql-hackers
Nazir, Andres, thank you both for help!
On Wed, Sep 13, 2023 at 10:10 PM Andres Freund <[email protected]> wrote:
> On 2023-09-13 16:04:00 +0300, Nazir Bilal Yavuz wrote:
> > local_blks_read became zero because:
> > 1_ One more cache hit. It was supposed to be local_blks_read but it is
> > local_blks_hit now. This is an assumption, I didn't check this deeply.
> > 2_ Before fcdda1e4b5, there was one local_blks_read coming from
> > buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
> > RBM_ZERO_ON_ERROR, NULL) in freespace.c -> ReadBuffer_common() ->
> > pgBufferUsage.local_blks_read++.
> > But buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
> > RBM_ZERO_ON_ERROR, NULL) is moved into the else case, so it didn't
> > called and local_blks_read isn't incremented.
>
> That imo is a legitimate difference / improvement. The read we previously
> did
> here was unnecessary.
>
>
> > local_blks_written is greater because of the combination of fcdda1e4b5
> > and 00d1e02be2.
> > In PG_15:
> > RelationGetBufferForTuple() -> ReadBufferBI(P_NEW, RBM_ZERO_AND_LOCK)
> > -> ReadBufferExtended() -> ReadBuffer_common() ->
> > pgBufferUsage.local_blks_written++; (called 5 times) [0]
> > In PG_16:
> > 1_ 5 of the local_blks_written is coming from:
> > RelationGetBufferForTuple() -> RelationAddBlocks() ->
> > ExtendBufferedRelBy() -> ExtendBufferedRelCommon() ->
> > ExtendBufferedRelLocal() -> pgBufferUsage.local_blks_written +=
> > extend_by; (extend_by is 1, this is called 5 times) [1]
> > 2_ 3 of the local_blks_written is coming from:
> > RelationGetBufferForTuple() -> RecordAndGetPageWithFreeSpace() ->
> > fsm_set_and_search() -> fsm_readbuf() -> fsm_extend() ->
> > ExtendBufferedRelTo() -> ExtendBufferedRelCommon() ->
> > ExtendBufferedRelLocal() -> pgBufferUsage.local_blks_written +=
> > extend_by; (extend_by is 3, this is called 1 time) [2]
> >
> > I think [0] is the same path as [1] but [2] is new. 'fsm extends'
> > wasn't counted in local_blks_written in PG_15. Calling
> > ExtendBufferedRelTo() from fsm_extend() caused 'fsm extends' to be
> > counted in local_blks_written. I am not sure which one is correct.
>
> I think it's correct to count the fsm writes here. The pg_stat_statement
> columns aren't specific to the main relation for or such... If anything it
> was
> a bug to not count them before.
>
Best regards,
Karina Litskevich
Postgres Professional: http://postgrespro.com/
^ permalink raw reply [nested|flat] 233+ messages in thread
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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 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 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 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 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 v56 4/6] 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 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 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 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 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 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 v36 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 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 v50 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 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 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 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 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 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 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 v25 7/8] 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 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 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 v51 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 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 v33 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 v37 5/6] 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 v52 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 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 v46 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 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 v47 5/7] 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 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 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 v40 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 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 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 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 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 v39 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 v43 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 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 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 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 v31 6/7] 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 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 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 v44 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 v42 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 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 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 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 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 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 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 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 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 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 v50 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 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 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 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 v56 4/6] 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 v29 6/7] 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 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 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 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 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 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 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 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 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 v33 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 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 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 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 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 v56 4/6] 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 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 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 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 v32 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 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 v57 4/6] 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 v50 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 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 v35 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 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 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 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 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 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 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 v49 5/7] Doc part of shared-memory based stats collector. Kyotaro Horiguchi <[email protected]>
2023-09-11 06:08 BufferUsage counters' values have changed Karina Litskevich <[email protected]>
2023-09-11 06:23 ` Re: BufferUsage counters' values have changed Karina Litskevich <[email protected]>
2023-09-13 18:59 ` Re: BufferUsage counters' values have changed Andres Freund <[email protected]>
2023-09-13 13:04 ` Re: BufferUsage counters' values have changed Nazir Bilal Yavuz <[email protected]>
2023-09-13 19:10 ` Re: BufferUsage counters' values have changed Andres Freund <[email protected]>
2023-09-15 07:37 ` Re: BufferUsage counters' values have changed Karina Litskevich <[email protected]>
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