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Add option SKIP_LOCKED to VACUUM and ANALYZE

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When specified, this option allows VACUUM to skip the work on a relation
if there is a conflicting lock on it when trying to open it at the
beginning of its processing.

Similarly to autovacuum, this comes with a couple of limitations while
the relation is processed which can cause the process to still block:
- when opening the relation indexes.
- when acquiring row samples for table inheritance trees, partition trees
or certain types of foreign tables, and that a lock is taken on some
leaves of such trees.

Author: Nathan Bossart
Reviewed-by: Michael Paquier, Andres Freund, Masahiko Sawada
Discussion: https://postgr.es/m/9EF7EBE4-720D-4CF1-9D0E-4403D7E92990@amazon.com
Discussion: https://postgr.es/m/20171201160907.27110.74730@wrigleys.postgresql.org
This commit is contained in:
Michael Paquier
2018-10-04 09:00:33 +09:00
parent d173652797
commit 803b1301e8
10 changed files with 333 additions and 7 deletions
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19
doc/src/sgml/ref/analyze.sgml
View File

@@ -27,6 +27,7 @@ ANALYZE [ VERBOSE ] [ <replaceable class="parameter">table_and_columns</replacea
<phrase>where <replaceable class="parameter">option</replaceable> can be one of:</phrase>
VERBOSE
SKIP_LOCKED
<phrase>and <replaceable class="parameter">table_and_columns</replaceable> is:</phrase>
@@ -76,6 +77,24 @@ ANALYZE [ VERBOSE ] [ <replaceable class="parameter">table_and_columns</replacea
</listitem>
</varlistentry>
<varlistentry>
<term><literal>SKIP_LOCKED</literal></term>
<listitem>
<para>
Specifies that <command>ANALYZE</command> should not wait for any
conflicting locks to be released when beginning work on a relation:
if a relation cannot be locked immediately without waiting, the relation
is skipped. Note that even with this option, <command>ANALYZE</command>
may still block when opening the relation's indexes or when acquiring
sample rows from partitions, table inheritance children, and some
types of foreign tables. Also, while <command>ANALYZE</command>
ordinarily processes all partitions of specified partitioned tables,
this option will cause <command>ANALYZE</command> to skip all
partitions if there is a conflicting lock on the partitioned table.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">table_name</replaceable></term>
<listitem>

21
doc/src/sgml/ref/vacuum.sgml
View File

@@ -31,6 +31,7 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ <replaceable class="paramet
VERBOSE
ANALYZE
DISABLE_PAGE_SKIPPING
SKIP_LOCKED
<phrase>and <replaceable class="parameter">table_and_columns</replaceable> is:</phrase>
@@ -160,6 +161,26 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ <replaceable class="paramet
</listitem>
</varlistentry>
<varlistentry>
<term><literal>SKIP_LOCKED</literal></term>
<listitem>
<para>
Specifies that <command>VACUUM</command> should not wait for any
conflicting locks to be released when beginning work on a relation:
if a relation cannot be locked immediately without waiting, the relation
is skipped. Note that even with this option,
<command>VACUUM</command> may still block when opening the relation's
indexes. Additionally, <command>VACUUM ANALYZE</command> may still
block when acquiring sample rows from partitions, table inheritance
children, and some types of foreign tables. Also, while
<command>VACUUM</command> ordinarily processes all partitions of
specified partitioned tables, this option will cause
<command>VACUUM</command> to skip all partitions if there is a
conflicting lock on the partitioned table.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">table_name</replaceable></term>
<listitem>