diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/config.sgml | 83 | ||||
| -rw-r--r-- | doc/src/sgml/monitoring.sgml | 86 | ||||
| -rw-r--r-- | doc/src/sgml/wal.sgml | 15 |
3 files changed, 2 insertions, 182 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index f129a875014..45bd1f1b7e3 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -3588,89 +3588,6 @@ include_dir 'conf.d' </variablelist> </sect2> - <sect2 id="runtime-config-wal-recovery"> - - <title>Recovery</title> - - <indexterm> - <primary>configuration</primary> - <secondary>of recovery</secondary> - <tertiary>general settings</tertiary> - </indexterm> - - <para> - This section describes the settings that apply to recovery in general, - affecting crash recovery, streaming replication and archive-based - replication. - </para> - - - <variablelist> - <varlistentry id="guc-recovery-prefetch" xreflabel="recovery_prefetch"> - <term><varname>recovery_prefetch</varname> (<type>boolean</type>) - <indexterm> - <primary><varname>recovery_prefetch</varname> configuration parameter</primary> - </indexterm> - </term> - <listitem> - <para> - Whether to try to prefetch blocks that are referenced in the WAL that - are not yet in the buffer pool, during recovery. Prefetching blocks - that will soon be needed can reduce I/O wait times in some workloads. - See also the <xref linkend="guc-wal-decode-buffer-size"/> and - <xref linkend="guc-maintenance-io-concurrency"/> settings, which limit - prefetching activity. - This setting is disabled by default. - </para> - <para> - This feature currently depends on an effective - <function>posix_fadvise</function> function, which some - operating systems lack. - </para> - </listitem> - </varlistentry> - - <varlistentry id="guc-recovery-prefetch-fpw" xreflabel="recovery_prefetch_fpw"> - <term><varname>recovery_prefetch_fpw</varname> (<type>boolean</type>) - <indexterm> - <primary><varname>recovery_prefetch_fpw</varname> configuration parameter</primary> - </indexterm> - </term> - <listitem> - <para> - Whether to prefetch blocks that were logged with full page images, - during recovery. Often this doesn't help, since such blocks will not - be read the first time they are needed and might remain in the buffer - pool after that. However, on file systems with a block size larger - than - <productname>PostgreSQL</productname>'s, prefetching can avoid a - costly read-before-write when blocks are later written. - The default is off. - </para> - </listitem> - </varlistentry> - - <varlistentry id="guc-wal-decode-buffer-size" xreflabel="wal_decode_buffer_size"> - <term><varname>wal_decode_buffer_size</varname> (<type>integer</type>) - <indexterm> - <primary><varname>wal_decode_buffer_size</varname> configuration parameter</primary> - </indexterm> - </term> - <listitem> - <para> - A limit on how far ahead the server can look in the WAL, to find - blocks to prefetch. Setting it too high might be counterproductive, - if it means that data falls out of the - kernel cache before it is needed. If this value is specified without - units, it is taken as bytes. - The default is 512kB. - </para> - </listitem> - </varlistentry> - - </variablelist> - </sect2> - <sect2 id="runtime-config-wal-archive-recovery"> <title>Archive Recovery</title> diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 370cdc2e1a1..dcbb10fb6ff 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -338,13 +338,6 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser </row> <row> - <entry><structname>pg_stat_prefetch_recovery</structname><indexterm><primary>pg_stat_prefetch_recovery</primary></indexterm></entry> - <entry>Only one row, showing statistics about blocks prefetched during recovery. - See <xref linkend="pg-stat-prefetch-recovery-view"/> for details. - </entry> - </row> - - <row> <entry><structname>pg_stat_subscription</structname><indexterm><primary>pg_stat_subscription</primary></indexterm></entry> <entry>At least one row per subscription, showing information about the subscription workers. @@ -2948,78 +2941,6 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i copy of the subscribed tables. </para> - <table id="pg-stat-prefetch-recovery-view" xreflabel="pg_stat_prefetch_recovery"> - <title><structname>pg_stat_prefetch_recovery</structname> View</title> - <tgroup cols="3"> - <thead> - <row> - <entry>Column</entry> - <entry>Type</entry> - <entry>Description</entry> - </row> - </thead> - - <tbody> - <row> - <entry><structfield>prefetch</structfield></entry> - <entry><type>bigint</type></entry> - <entry>Number of blocks prefetched because they were not in the buffer pool</entry> - </row> - <row> - <entry><structfield>skip_hit</structfield></entry> - <entry><type>bigint</type></entry> - <entry>Number of blocks not prefetched because they were already in the buffer pool</entry> - </row> - <row> - <entry><structfield>skip_new</structfield></entry> - <entry><type>bigint</type></entry> - <entry>Number of blocks not prefetched because they were new (usually relation extension)</entry> - </row> - <row> - <entry><structfield>skip_fpw</structfield></entry> - <entry><type>bigint</type></entry> - <entry>Number of blocks not prefetched because a full page image was included in the WAL and <xref linkend="guc-recovery-prefetch-fpw"/> was set to <literal>off</literal></entry> - </row> - <row> - <entry><structfield>skip_seq</structfield></entry> - <entry><type>bigint</type></entry> - <entry>Number of blocks not prefetched because of repeated access</entry> - </row> - <row> - <entry><structfield>distance</structfield></entry> - <entry><type>integer</type></entry> - <entry>How far ahead of recovery the prefetcher is currently reading, in bytes</entry> - </row> - <row> - <entry><structfield>queue_depth</structfield></entry> - <entry><type>integer</type></entry> - <entry>How many prefetches have been initiated but are not yet known to have completed</entry> - </row> - <row> - <entry><structfield>avg_distance</structfield></entry> - <entry><type>float4</type></entry> - <entry>How far ahead of recovery the prefetcher is on average, while recovery is not idle</entry> - </row> - <row> - <entry><structfield>avg_queue_depth</structfield></entry> - <entry><type>float4</type></entry> - <entry>Average number of prefetches in flight while recovery is not idle</entry> - </row> - </tbody> - </tgroup> - </table> - - <para> - The <structname>pg_stat_prefetch_recovery</structname> view will contain only - one row. It is filled with nulls if recovery is not running or WAL - prefetching is not enabled. See <xref linkend="guc-recovery-prefetch"/> - for more information. The counters in this view are reset whenever the - <xref linkend="guc-recovery-prefetch"/>, - <xref linkend="guc-recovery-prefetch-fpw"/> or - <xref linkend="guc-maintenance-io-concurrency"/> setting is changed and - the server configuration is reloaded. - </para> - <table id="pg-stat-subscription" xreflabel="pg_stat_subscription"> <title><structname>pg_stat_subscription</structname> View</title> <tgroup cols="1"> @@ -5152,11 +5073,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i all the counters shown in the <structname>pg_stat_bgwriter</structname> view, <literal>archiver</literal> to reset all the counters shown in - the <structname>pg_stat_archiver</structname> view, - <literal>wal</literal> to reset all the counters shown in the - <structname>pg_stat_wal</structname> view or - <literal>prefetch_recovery</literal> to reset all the counters shown - in the <structname>pg_stat_prefetch_recovery</structname> view. + the <structname>pg_stat_archiver</structname> view or <literal>wal</literal> + to reset all the counters shown in the <structname>pg_stat_wal</structname> view. </para> <para> This function is restricted to superusers by default, but other users diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml index 9606c617d41..60f066d2473 100644 --- a/doc/src/sgml/wal.sgml +++ b/doc/src/sgml/wal.sgml @@ -803,21 +803,6 @@ counted as <literal>wal_write</literal> and <literal>wal_sync</literal> in <structname>pg_stat_wal</structname>, respectively. </para> - - <para> - The <xref linkend="guc-recovery-prefetch"/> parameter can - be used to improve I/O performance during recovery by instructing - <productname>PostgreSQL</productname> to initiate reads - of disk blocks that will soon be needed but are not currently in - <productname>PostgreSQL</productname>'s buffer pool. - The <xref linkend="guc-maintenance-io-concurrency"/> and - <xref linkend="guc-wal-decode-buffer-size"/> settings limit prefetching - concurrency and distance, respectively. The - prefetching mechanism is most likely to be effective on systems - with <varname>full_page_writes</varname> set to - <varname>off</varname> (where that is safe), and where the working - set is larger than RAM. By default, prefetching in recovery is disabled. - </para> </sect1> <sect1 id="wal-internals"> |