diff options
| author | Robert Haas | 2016-06-17 19:48:57 +0000 |
|---|---|---|
| committer | Robert Haas | 2016-06-17 19:48:57 +0000 |
| commit | ede62e56fbe809baa1a7bc3873d82f12ffe7540b (patch) | |
| tree | bed6a8e258dc9148b2141b0a8e112a0b864bc283 /doc/src/sgml/ref/vacuum.sgml | |
| parent | 20eb2731b7775f3381939d2667b6aa8ba62ab2c5 (diff) | |
Add VACUUM (DISABLE_PAGE_SKIPPING) for emergencies.
If you really want to vacuum every single page in the relation,
regardless of apparent visibility status or anything else, you can use
this option. In previous releases, this behavior could be achieved
using VACUUM (FREEZE), but because we can now recognize all-frozen
pages as not needing to be frozen again, that no longer works. There
should be no need for routine use of this option, but maybe bugs or
disaster recovery will necessitate its use.
Patch by me, reviewed by Andres Freund.
Diffstat (limited to 'doc/src/sgml/ref/vacuum.sgml')
| -rw-r--r-- | doc/src/sgml/ref/vacuum.sgml | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/doc/src/sgml/ref/vacuum.sgml b/doc/src/sgml/ref/vacuum.sgml index 19fd748dde0..dee1c5bad31 100644 --- a/doc/src/sgml/ref/vacuum.sgml +++ b/doc/src/sgml/ref/vacuum.sgml @@ -21,7 +21,7 @@ PostgreSQL documentation <refsynopsisdiv> <synopsis> -VACUUM [ ( { FULL | FREEZE | VERBOSE | ANALYZE } [, ...] ) ] [ <replaceable class="PARAMETER">table_name</replaceable> [ (<replaceable class="PARAMETER">column_name</replaceable> [, ...] ) ] ] +VACUUM [ ( { FULL | FREEZE | VERBOSE | ANALYZE | DISABLE_PAGE_SKIPPING } [, ...] ) ] [ <replaceable class="PARAMETER">table_name</replaceable> [ (<replaceable class="PARAMETER">column_name</replaceable> [, ...] ) ] ] VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ <replaceable class="PARAMETER">table_name</replaceable> ] VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] ANALYZE [ <replaceable class="PARAMETER">table_name</replaceable> [ (<replaceable class="PARAMETER">column_name</replaceable> [, ...] ) ] ] </synopsis> @@ -130,6 +130,25 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] ANALYZE [ <replaceable class="PARAMETER"> </varlistentry> <varlistentry> + <term><literal>DISABLE_PAGE_SKIPPING</literal></term> + <listitem> + <para> + Normally, <command>VACUUM</> will skip pages based on the <link + linkend="vacuum-for-visibility-map">visibility map</>. Pages where + all tuples are known to be frozen can always be skipped, and those + where all tuples are known to be visible to all transactions may be + skipped except when performing an aggressive vacuum. Furthermore, + except when performing an aggressive vacuum, some pages may be skipped + in order to avoid waiting for other sessions to finish using them. + This option disables all page-skipping behavior, and is intended to + be used only the contents of the visibility map are thought to + be suspect, which should happen only if there is a hardware or software + issue causing database corruption. + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><replaceable class="PARAMETER">table_name</replaceable></term> <listitem> <para> |