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| author | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2018-12-17 11:44:36 -0300 |
|---|---|---|
| committer | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2018-12-17 11:44:36 -0300 |
| commit | 1e6240a3fe919e19676875927681a861e13f93c2 (patch) | |
| tree | 31cd1f3eeadfc20741059367d3edf97b500f9806 /doc/src | |
| parent | 3abb11e55b0a8408cd91fe341cda1f568774df58 (diff) | |
| download | postgresql-1e6240a3fe919e19676875927681a861e13f93c2.tar.gz postgresql-1e6240a3fe919e19676875927681a861e13f93c2.zip | |
Clarify runtime pruning in EXPLAIN
Author: Amit Langote
Reviewed-by: David Rowley
Discussion: https://postgr.es/m/002dec69-9afb-b621-5630-235eceafe0bd@lab.ntt.co.jp
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ddl.sgml | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml index 1925ff45509..85e43589882 100644 --- a/doc/src/sgml/ddl.sgml +++ b/doc/src/sgml/ddl.sgml @@ -4421,8 +4421,12 @@ EXPLAIN SELECT count(*) FROM measurement WHERE logdate >= DATE '2008-01-01'; query, partition pruning is performed whenever one of the execution parameters being used by partition pruning changes. Determining if partitions were pruned during this phase requires - careful inspection of the <literal>nloops</literal> property in - the <command>EXPLAIN ANALYZE</command> output. + careful inspection of the <literal>loops</literal> property in + the <command>EXPLAIN ANALYZE</command> output. Subplans + corresponding to different partitions may have different values + for it depending on how many times each of them was pruned during + execution. Some may be shown as <literal>(never executed)</literal> + if they were pruned every time. </para> </listitem> </itemizedlist> |