Wiki / Configuration Parameters
vacuum_multixact_freeze_table_age
VACUUM performs an aggressive scan if the table's pg_class.relminmxid field has reached the age specified by this setting. An aggressive scan differs from a regular VACUUM in that it visits every page that might contain unfrozen XIDs or MXIDs, not just those that might contain dead tuples. The default is 150 million multixacts. Although users can set this value anywhere from zero to two billion, VACUUM will silently limit the effective value to 95% of autovacuum_multixact_freeze_max_age, so that a periodic manual VACUUM has a chance to run before an anti-wraparound is launched for the table. For more information see Section 24.1.5.1.
English manual coverage begins with PostgreSQL 7.4. Source history and runtime observations have their own recorded version boundaries.
Reading PG 18·Select a recorded version
- boot val
- 150000000
- category
- Vacuuming / Freezing
- context
- user
- doc same as
- Unknown
- documented
- true
- enumvals
- Unknown
- extra desc
- Unknown
- lang
- en
- max val
- 2000000000
- metadata version
- 18
- min val
- 0
- name
- vacuum_multixact_freeze_table_age
- short desc
- Multixact age at which VACUUM should scan whole table to freeze tuples.
- source
- pg-settings-source-snapshot
- unit
- Unknown
- vartype
- integer
Definition PG 18
VACUUM performs an aggressive scan if the table's
pg_class.relminmxid field has reached
the age specified by this setting. An aggressive scan differs from
a regular VACUUM in that it visits every page that might
contain unfrozen XIDs or MXIDs, not just those that might contain dead
tuples. The default is 150 million multixacts.
Although users can set this value anywhere from zero to two billion,
VACUUM will silently limit the effective value to 95% of
autovacuum_multixact_freeze_max_age, so that a
periodic manual VACUUM has a chance to run before an
anti-wraparound is launched for the table.
For more information see Section 24.1.5.1.
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Complete source facts
doc html
<p>
<code class="command">VACUUM</code> performs an aggressive scan if the table's
<code class="structname">pg_class</code>.<code class="structfield">relminmxid</code> field has reached
the age specified by this setting. An aggressive scan differs from
a regular <code class="command">VACUUM</code> in that it visits every page that might
contain unfrozen XIDs or MXIDs, not just those that might contain dead
tuples. The default is 150 million multixacts.
Although users can set this value anywhere from zero to two billion,
<code class="command">VACUUM</code> will silently limit the effective value to 95% of
<a class="xref" href="/docs/18/runtime-config-vacuum.html#GUC-AUTOVACUUM-MULTIXACT-FREEZE-MAX-AGE">autovacuum_multixact_freeze_max_age</a>, so that a
periodic manual <code class="command">VACUUM</code> has a chance to run before an
anti-wraparound is launched for the table.
For more information see <a class="xref" href="/docs/18/routine-vacuuming.html#VACUUM-FOR-MULTIXACT-WRAPAROUND" title="24.1.5.1. Multixacts and Wraparound">Section 24.1.5.1</a>.
</p>documentation revision
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Full definition and evidence JSON
Definition sources
center · PostgreSQL 18 · wiki-repair-20261023:e2e9a26d829957cd969d1c3f313b56bbb5e5005094d2742dc808d83c201b6921
Text language: en · wiki-repair-20261023:e2e9a26d829957cd969d1c3f313b56bbb5e5005094d2742dc808d83c201b6921