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doc: simplify docs about analyze and inheritance/partitions
Discussion: https://postgr.es/m/YxAqYijOsLzgLQgy@momjian.us Backpatch-through: 10
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doc/src/sgml/ref/analyze.sgml

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@@ -250,12 +250,13 @@ ANALYZE [ VERBOSE ] [ <replaceable class="parameter">table_and_columns</replacea
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</para>
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<para>
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If the table being analyzed has one or more children,
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<command>ANALYZE</command> will gather statistics twice: once on the
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rows of the parent table only, and a second time on the rows of the
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parent table with all of its children. This second set of statistics
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is needed when planning queries that traverse the entire inheritance
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tree. The autovacuum daemon, however, will only consider inserts or
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If the table being analyzed has inheritance children,
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<command>ANALYZE</command> gathers two sets of statistics: one on the rows
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of the parent table only, and a second including rows of both the parent
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table and all of its children. This second set of statistics is needed when
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planning queries that process the inheritance tree as a whole. The child
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tables themselves are not individually analyzed in this case.
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The autovacuum daemon, however, will only consider inserts or
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updates on the parent table itself when deciding whether to trigger an
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automatic analyze for that table. If that table is rarely inserted into
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or updated, the inheritance statistics will not be up to date unless you
@@ -271,15 +272,6 @@ ANALYZE [ VERBOSE ] [ <replaceable class="parameter">table_and_columns</replacea
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partitioning it's guaranteed to be empty.
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</para>
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<para>
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By contrast, if the table being analyzed has inheritance children,
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<command>ANALYZE</command> gathers two sets of statistics: one on the rows
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of the parent table only, and a second including rows of both the parent
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table and all of its children. This second set of statistics is needed when
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planning queries that process the inheritance tree as a whole. The child
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tables themselves are not individually analyzed in this case.
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</para>
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<para>
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The autovacuum daemon does not process partitioned tables, nor does it
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process inheritance parents if only the children are ever modified.

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