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authorAmit Kapila2020-04-14 02:40:27 +0000
committerAmit Kapila2020-04-14 02:40:27 +0000
commita6fea120a7e3858e642bb5e96027f166a1a6f134 (patch)
tree6dc527a06a5a8f437ec06eb52edc45157e73a111 /doc/src/sgml/ref/vacuum.sgml
parent826ee1a019127d611bb0fd22ca878142bfb077ac (diff)
Comments and doc fixes for commit 40d964ec99.
Reported-by: Justin Pryzby Author: Justin Pryzby, with few changes by me Reviewed-by: Amit Kapila and Sawada Masahiko Discussion: https://postgr.es/m/[email protected]
Diffstat (limited to 'doc/src/sgml/ref/vacuum.sgml')
-rw-r--r--doc/src/sgml/ref/vacuum.sgml22
1 files changed, 11 insertions, 11 deletions
diff --git a/doc/src/sgml/ref/vacuum.sgml b/doc/src/sgml/ref/vacuum.sgml
index 846056a353d..442977a50d5 100644
--- a/doc/src/sgml/ref/vacuum.sgml
+++ b/doc/src/sgml/ref/vacuum.sgml
@@ -232,15 +232,15 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ <replaceable class="paramet
<term><literal>PARALLEL</literal></term>
<listitem>
<para>
- Perform vacuum index and cleanup index phases of <command>VACUUM</command>
+ Perform index vacuum and index cleanup phases of <command>VACUUM</command>
in parallel using <replaceable class="parameter">integer</replaceable>
- background workers (for the detail of each vacuum phases, please
+ background workers (for the details of each vacuum phase, please
refer to <xref linkend="vacuum-phases"/>). If the
- <literal>PARALLEL</literal> option is omitted, then
- <command>VACUUM</command> decides the number of workers based on number
- of indexes that support parallel vacuum operation on the relation which
- is further limited by <xref linkend="guc-max-parallel-workers-maintenance"/>.
- The index can participate in a parallel vacuum if and only if the size
+ <literal>PARALLEL</literal> option is omitted, then the number of workers
+ is determined based on the number of indexes that support parallel vacuum
+ operation on the relation, and is further limited by <xref
+ linkend="guc-max-parallel-workers-maintenance"/>.
+ An index can participate in parallel vacuum if and only if the size
of the index is more than <xref linkend="guc-min-parallel-index-scan-size"/>.
Please note that it is not guaranteed that the number of parallel workers
specified in <replaceable class="parameter">integer</replaceable> will
@@ -248,7 +248,7 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ <replaceable class="paramet
workers than specified, or even with no workers at all. Only one worker
can be used per index. So parallel workers are launched only when there
are at least <literal>2</literal> indexes in the table. Workers for
- vacuum launches before starting each phase and exit at the end of
+ vacuum are launched before the start of each phase and exit at the end of
the phase. These behaviors might change in a future release. This
option can't be used with the <literal>FULL</literal> option.
</para>
@@ -358,8 +358,8 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ <replaceable class="paramet
</para>
<para>
- The <option>PARALLEL</option> option is used only for vacuum purpose.
- Even if this option is specified with <option>ANALYZE</option> option
+ The <option>PARALLEL</option> option is used only for vacuum purposes.
+ If this option is specified with the <option>ANALYZE</option> option,
it does not affect <option>ANALYZE</option>.
</para>
@@ -367,7 +367,7 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ <replaceable class="paramet
<command>VACUUM</command> causes a substantial increase in I/O traffic,
which might cause poor performance for other active sessions. Therefore,
it is sometimes advisable to use the cost-based vacuum delay feature. For
- parallel vacuum, each worker sleeps proportional to the work done by that
+ parallel vacuum, each worker sleeps in proportion to the work done by that
worker. See <xref linkend="runtime-config-resource-vacuum-cost"/> for
details.
</para>