8000 Document pg_get_multixact_members(). · postgres/postgres@0ee7f51 · GitHub
[go: up one dir, main page]

Skip to content

Commit 0ee7f51

Browse files
nathan-bossartÁlvaro Herrera
andcommitted
Document pg_get_multixact_members().
Oversight in commit 0ac5ad5. Author: Sami Imseih <samimseih@gmail.com> Co-authored-by: Álvaro Herrera <alvherre@kurilemu.de> Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com> Discussion: https://postgr.es/m/20150619215231.GT133018%40postgresql.org Discussion: https://postgr.es/m/CAA5RZ0sjQDDwJfMRb%3DZ13nDLuRpF13ME2L_BdGxi0op8RKjmDg%40mail.gmail.com Backpatch-through: 13
1 parent d0a695c commit 0ee7f51

File tree

2 files changed

+31
-2
lines changed

2 files changed

+31
-2
lines changed

doc/src/sgml/func.sgml

Lines changed: 27 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -23394,6 +23394,31 @@ SELECT collation for ('foo' COLLATE "de_DE");
2339423394
a subtransaction ID.
2339523395
</para></entry>
2339623396
</row>
23397+
23398+
<row>
23399+
<entry role="func_table_entry"><para role="func_signature">
23400+
<indexterm>
23401+
<primary>pg_get_multixact_members</primary>
23402+
</indexterm>
23403+
<function>pg_get_multixact_members</function> ( <parameter>multixid</parameter> <type>xid</type> )
23404+
<returnvalue>setof record</returnvalue>
23405+
( <parameter>xid</parameter> <type>xid</type>,
23406+
<parameter>mode</parameter> <type>text</type> )
23407+
</para>
23408+
<para>
23409+
Returns the transaction ID and lock mode for each member of the
23410+
specified multixact ID. The lock modes <literal>forupd</literal>,
23411+
<literal>fornokeyupd</literal>, <literal>sh</literal>, and
23412+
<literal>keysh</literal> correspond to the row-level locks
23413+
<literal>FOR UPDATE</literal>, <literal>FOR NO KEY UPDATE</literal>,
23414+
<literal>FOR SHARE</literal>, and <literal>FOR KEY SHARE</literal>,
23415+
respectively, as described in <xref linkend="locking-rows"/>. Two
23416+
additional modes are specific to multixacts:
23417+
<literal>nokeyupd</literal>, used by updates that do not modify key
23418+
columns, and <literal>upd</literal>, used by updates or deletes that
23419+
modify key columns.
23420+
</para></entry>
23421+
</row>
2339723422
</tbody>
2339823423
</tgroup>
2339923424
</table>
@@ -23402,7 +23427,8 @@ SELECT collation for ('foo' COLLATE "de_DE");
2340223427
The internal transaction ID type <type>xid</type> is 32 bits wide and
2340323428
wraps around every 4 billion transactions. However,
2340423429
the functions shown in <xref linkend="functions-pg-snapshot"/>, except
23405-
<function>age</function> and <function>mxid_age</function>, use a
23430+
<function>age</function>, <function>mxid_age</function>, and
23431+
<function>pg_get_multixact_members</function>, use a
2340623432
64-bit type <type>xid8</type> that does not wrap around during the life
2340723433
of an installation, and can be converted to <type>xid</type> by casting if
2340823434
required. The data type <type>pg_snapshot</type> stores information about

doc/src/sgml/maintenance.sgml

Lines changed: 4 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -690,7 +690,10 @@ HINT: Stop the postmaster and vacuum that database in single-user mode.
690690
careful aging management, storage cleanup, and wraparound handling.
691691
There is a separate storage area which holds the list of members in
692692
each multixact, which also uses a 32-bit counter and which must also
693-
be managed.
693+
be managed. The system function
694+
<function>pg_get_multixact_members()</function> described in
695+
<xref linkend="functions-pg-snapshot"/> can be used to examine the
696+
transaction IDs associated with a multixact ID.
694697
</para>
695698

696699
<para>

0 commit comments

Comments
 (0)
0