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author | Robert Haas <rhaas@postgresql.org> | 2010-06-15 18:43:35 +0000 |
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committer | Robert Haas <rhaas@postgresql.org> | 2010-06-15 18:43:35 +0000 |
commit | 4a969085753d4e6586e60e613f160bf3a956b75d (patch) | |
tree | e6d56614d3b5a919e55aa50010d4f2a3df39e54c /doc/src | |
parent | 48a7245391687cefd21ffe7597eff553f6b29960 (diff) | |
download | postgresql-4a969085753d4e6586e60e613f160bf3a956b75d.tar.gz postgresql-4a969085753d4e6586e60e613f160bf3a956b75d.zip |
Document new 9.0 behavior of ANALYZE on inheritance hierarchies.
In particular, note that autovacuum does not yet understand that it might
need to vacuum inheritance parents as a result of changes to the child
tables.
Diffstat (limited to 'doc/src')
-rw-r--r-- | doc/src/sgml/ref/analyze.sgml | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/doc/src/sgml/ref/analyze.sgml b/doc/src/sgml/ref/analyze.sgml index 1f2e4c1bad7..98dcbf0ed80 100644 --- a/doc/src/sgml/ref/analyze.sgml +++ b/doc/src/sgml/ref/analyze.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/analyze.sgml,v 1.29 2010/04/03 07:22:57 petere Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/analyze.sgml,v 1.30 2010/06/15 18:43:35 rhaas Exp $ PostgreSQL documentation --> @@ -176,6 +176,17 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ ( <re <command>ALTER TABLE ... ALTER COLUMN ... SET (n_distinct = ...)</> (see <xref linkend="sql-altertable">). </para> + + <para> + If the table being analyzed has one or more children, + <command>ANALYZE</command> will gather statistics twice: once on the + rows of the parent table only, and a second time on the rows of the + parent table with all of its children. The autovacuum daemon, however, + will only consider inserts or updates on the parent table when deciding + whether to trigger an automatic analyze. If that table is rarely + inserted into or updated, the inheritance statistics will not be up to date + unless you run <command>ANALYZE</command> manually. + </para> </refsect1> <refsect1> |