pgpool2.git / summary / log / commit / refs
commit cb35c9b8d5a1980dc14ffdd99c01e17599fa8873
Author: Tatsuo Ishii <ishii@sraoss.co.jp>
Date: Sun Jan 26 11:16:43 2020 +0000
Doc: add show pool_health_check_stats reference manual.
Forgot in the previous commit.
doc/src/sgml/ref/show_pool_health_check_stats.sgml | 273 +++++++++++++++++++++
1 file changed, 273 insertions(+)
diff --git a/doc/src/sgml/ref/show_pool_health_check_stats.sgml b/doc/src/sgml/ref/show_pool_health_check_stats.sgml
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+<!--
+ doc/src/sgml/ref/show_pool_health_check_stats.sgml
+ Pgpool-II documentation
+ -->
+
+<refentry id="SQL-SHOW-POOL-HEALTH-CHECK-STATS">
+ <indexterm zone="sql-show-pool-health-check-stats">
+ <primary>SHOW POOL_HEALTH_CHECK_STATS</primary>
+ </indexterm>
+
+ <refmeta>
+ <refentrytitle>SHOW POOL HEALTH_CHECK_STATS</refentrytitle>
+ <manvolnum>1</manvolnum>
+ <refmiscinfo>SQL - Language Statements</refmiscinfo>
+ </refmeta>
+
+ <refnamediv>
+ <refname>SHOW POOL_HEALTH_CHECK_STATS</refname>
+ <refpurpose>
+ show health check status data
+ </refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <synopsis>
+ SHOW POOL_HEALTH_CHECK_STATS
+ </synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>
+ <command>SHOW POOL_HEALTH_CHECK_STATS</command> displays health
+ check (see <xref linkend="runtime-config-health-check">) statistic
+ data mostly collected by health check process. This command helps
+ <productname>Pgpool-II</productname> admin to study events related
+ to health check. For example, admin can easily locate the failover
+ event in the log file by looking at "last_failed_health_check"
+ column. Another example is finding unstable connection to backend
+ by evaluating "average_retry_count" column. If particular node
+ shows higher retry count than other node, there may be problem to
+ the connection to the backend.
+ </para>
+
+ <para>
+ <xref linkend="health-check-stats-data-table"> shows each column name and its description.
+ </para>
+
+ <table id="health-check-stats-data-table">
+ <title>Statistics data shown by pool_health_check_stats command</title>
+ <tgroup cols="2">
+ <thead>
+ <row>
+ <entry>Column Name</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+
+ <tbody>
+
+ <row>
+ <entry>node_id</entry>
+ <entry>
+ Backend node id.
+ </entry>
+ </row>
+
+ <row>
+ <entry>hostname</entry>
+ <entry>
+ Backend hostname or UNIX domain socket path.
+ </entry>
+ </row>
+
+ <row>
+ <entry>port</entry>
+ <entry>
+ Backend port number.
+ </entry>
+ </row>
+
+ <row>
+ <entry>status</entry>
+ <entry>
+ Backend status. One of up, down, waiting, unused or quarantine.
+ </entry>
+ </row>
+
+ <row>
+ <entry>role</entry>
+ <entry>
+ Role of the node. Either primary or standby in streaming
+ replication mode. Either master or slave in other mode.
+ </entry>
+ </row>
+
+ <row>
+ <entry>last_status_change</entry>
+ <entry>
+ Timestamp of last backend status changed.
+ </entry>
+ </row>
+
+ <row>
+ <entry>total_count</entry>
+ <entry>
+ Number of health check count in total.
+ </entry>
+ </row>
+
+ <row>
+ <entry>success_count</entry>
+ <entry>
+ Number of successful health check count in total.
+ </entry>
+ </row>
+
+ <row>
+ <entry>fail_count</entry>
+ <entry>
+ Number of failed health check count in total.
+ </entry>
+ </row>
+
+ <row>
+ <entry>skip_count</entry>
+ <entry>
+ Number of skipped health check count in total. If the node is
+ already down, health check skips the node.
+ </entry>
+ </row>
+
+ <row>
+ <entry>retry_count</entry>
+ <entry>
+ Number of retried health check count in total.
+ </entry>
+ </row>
+
+ <row>
+ <entry>average_retry_count</entry>
+ <entry>
+ Number of average retried health check count in a health check
+ session.
+ </entry>
+ </row>
+
+ <row>
+ <entry>max_retry_count</entry>
+ <entry>
+ Number of maximum retried health check count in a health check
+ session.
+ </entry>
+ </row>
+
+ <row>
+ <entry>max_duration</entry>
+ <entry>
+ Maximum health check duration in Millie seconds. If a health
+ check session retries, the health check duration is sum of each
+ retried health check.
+ </entry>
+ </row>
+
+ <row>
+ <entry>min_duration</entry>
+ <entry>
+ Minimum health check duration in Millie seconds. If a health
+ check session retries, the health check duration is sum of each
+ retried health check.
+ </entry>
+ </row>
+
+ <row>
+ <entry>average_duration</entry>
+ <entry>
+ Average health check duration in Millie seconds. If a health
+ check session retries, the health check duration is sum of each
+ retried health check.
+ </entry>
+ </row>
+
+ <row>
+ <entry>last_health_check</entry>
+ <entry>
+ Timestamp of last health check.
+ </entry>
+ </row>
+
+ <row>
+ <entry>last_successful_health_check</entry>
+ <entry>
+ Timestamp of last successful health check. If heath check does
+ not succeeds yet, empty string.
+ </entry>
+ </row>
+
+ <row>
+ <entry>last_skip_health_check</entry>
+ <entry>
+ Timestamp of last skipped health check. If heath check is not
+ skipped yet, empty string. Note that it is possible that this
+ field is an empty string even if the status is down. In this
+ case failover was triggered by other than health check process.
+ </entry>
+ </row>
+
+ <row>
+ <entry>last_falied_health_check</entry>
+ <entry>
+ Timestamp of last failed health check. If heath check does not
+ fail yet, empty string. Note that it is possible that this
+ field is an empty string even if the status is down. In this
+ case failover was triggered by other than health check process.
+ </entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ Here is an example session:
+ <programlisting>
+test=# show pool_health_check_stats;
+-[ RECORD 1 ]----------------+--------------------
+node_id | 0
+hostname | /tmp
+port | 11002
+status | up
+role | primary
+last_status_change | 2020-01-26 19:08:45
+total_count | 27
+success_count | 27
+fail_count | 0
+skip_count | 0
+retry_count | 0
+average_retry_count | 0.000000
+max_retry_count | 0
+max_duration | 9
+min_duration | 2
+average_duration | 6.296296
+last_health_check | 2020-01-26 19:12:45
+last_successful_health_check | 2020-01-26 19:12:45
+last_skip_health_check |
+last_failed_health_check |
+-[ RECORD 2 ]----------------+--------------------
+node_id | 1
+hostname | /tmp
+port | 11003
+status | down
+role | standby
+last_status_change | 2020-01-26 19:11:48
+total_count | 19
+success_count | 12
+fail_count | 1
+skip_count | 6
+retry_count | 3
+average_retry_count | 0.230769
+max_retry_count | 3
+max_duration | 83003
+min_duration | 0
+average_duration | 6390.307692
+last_health_check | 2020-01-26 19:12:48
+last_successful_health_check | 2020-01-26 19:10:15
+last_skip_health_check | 2020-01-26 19:12:48
+last_failed_health_check | 2020-01-26 19:11:48
+ </programlisting>
+ </para>
+ </refsect1>
+
+</refentry>
[parent: 154d826b73a5]