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| author | Bruce Momjian <bruce@momjian.us> | 2022-09-02 23:32:18 -0400 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2022-09-02 23:32:18 -0400 |
| commit | a78c38417a6030c900853a31b776265e57ac7e48 (patch) | |
| tree | a8d15ac120df2b4cd4f72c5e964d03465ac29628 | |
| parent | 92cad1439f2b775211d34c7b8f42b87e02c68ace (diff) | |
| download | postgresql-a78c38417a6030c900853a31b776265e57ac7e48.tar.gz postgresql-a78c38417a6030c900853a31b776265e57ac7e48.zip | |
doc: simplify docs about analyze and inheritance/partitions
Discussion: https://postgr.es/m/YxAqYijOsLzgLQgy@momjian.us
Backpatch-through: 10
| -rw-r--r-- | doc/src/sgml/ref/analyze.sgml | 22 |
1 files changed, 7 insertions, 15 deletions
diff --git a/doc/src/sgml/ref/analyze.sgml b/doc/src/sgml/ref/analyze.sgml index 4b92362f18b..dbdc3a06961 100644 --- a/doc/src/sgml/ref/analyze.sgml +++ b/doc/src/sgml/ref/analyze.sgml @@ -251,12 +251,13 @@ ANALYZE [ VERBOSE ] [ <replaceable class="parameter">table_and_columns</replacea </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. This second set of statistics - is needed when planning queries that traverse the entire inheritance - tree. The autovacuum daemon, however, will only consider inserts or + If the table being analyzed has inheritance children, + <command>ANALYZE</command> gathers two sets of statistics: one on the rows + of the parent table only, and a second including rows of both the parent + table and all of its children. This second set of statistics is needed when + planning queries that process the inheritance tree as a whole. The child + tables themselves are not individually analyzed in this case. + The autovacuum daemon, however, will only consider inserts or updates on the parent table itself when deciding whether to trigger an automatic analyze for that table. If that table is rarely inserted into or updated, the inheritance statistics will not be up to date unless you @@ -273,15 +274,6 @@ ANALYZE [ VERBOSE ] [ <replaceable class="parameter">table_and_columns</replacea </para> <para> - By contrast, if the table being analyzed has inheritance children, - <command>ANALYZE</command> gathers two sets of statistics: one on the rows - of the parent table only, and a second including rows of both the parent - table and all of its children. This second set of statistics is needed when - planning queries that process the inheritance tree as a whole. The child - tables themselves are not individually analyzed in this case. - </para> - - <para> The autovacuum daemon does not process partitioned tables, nor does it process inheritance parents if only the children are ever modified. It is usually necessary to periodically run a manual |