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authorJohn Naylor <john.naylor@postgresql.org>2025-03-07 10:22:56 +0700
committerJohn Naylor <john.naylor@postgresql.org>2025-03-07 10:22:56 +0700
commitfcabc3adf889ebf2c2d8d1c084989f5fd95aac2f (patch)
treeff20ccae9fdb1e0eaddd4eb29da9a94c37eae306 /doc/src
parent5f8eb25706b62923c53172e453c8a4dedd877a3d (diff)
downloadpostgresql-fcabc3adf889ebf2c2d8d1c084989f5fd95aac2f.tar.gz
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Doc: correct aggressive vacuum threshold for multixact members storage
The threshold is two billion members, which was interpreted as 2GB in the documentation. Fix to reflect that each member takes up five bytes, which translates to about 10GB. This is not exact, because of page boundaries. While at it, mention the maximum size 20GB. This has been wrong since commit c552e171d16e, so backpatch to version 14. Author: Alex Friedman <alexf01@gmail.com> Reviewed-by: Sami Imseih <samimseih@gmail.com> Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com> Discussion: https://postgr.es/m/CACbFw60UOk6fCC02KsyT3OfU9Dnuq5roYxdw2aFisiN_p1L0bg@mail.gmail.com Backpatch-through: 14
Diffstat (limited to 'doc/src')
-rw-r--r--doc/src/sgml/maintenance.sgml5
1 files changed, 3 insertions, 2 deletions
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index b5b9da7f8a9..600e4b3f2f3 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -811,10 +811,11 @@ HINT: Execute a database-wide VACUUM in that database.
As a safety device, an aggressive vacuum scan will
occur for any table whose multixact-age is greater than <xref
linkend="guc-autovacuum-multixact-freeze-max-age"/>. Also, if the
- storage occupied by multixacts members exceeds 2GB, aggressive vacuum
+ storage occupied by multixacts members exceeds about 10GB, aggressive vacuum
scans will occur more often for all tables, starting with those that
have the oldest multixact-age. Both of these kinds of aggressive
- scans will occur even if autovacuum is nominally disabled.
+ scans will occur even if autovacuum is nominally disabled. The members storage
+ area can grow up to about 20GB before reaching wraparound.
</para>
<para>