postgres.git / summary / log / commit / refs
commit f760a8b5cc1fa8c9d341faaf2cbda3b94d5a20d9
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Mon Dec 17 14:44:19 2018 +0000
First released in: 12.0, 11.2
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
doc/src/sgml/ddl.sgml | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 5ae3cacbf0e..5e5c3d7057b 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3921,8 +3921,12 @@ 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>
[parent: f88dd4fa43b4]