database/postgres
database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-05-11 05:41:32 +03:00
Code

Clarify runtime pruning in EXPLAIN

Browse Source 
Author: Amit Langote
Reviewed-by: David Rowley
Discussion: https://postgr.es/m/002dec69-9afb-b621-5630-235eceafe0bd@lab.ntt.co.jp
This commit is contained in:
Alvaro Herrera 2018-12-17 11:44:19 -03:00
parent f88dd4fa43
commit f760a8b5cc
1 changed files with 6 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
doc/src/sgml/ddl.sgml
View File

@ -3921,8 +3921,12 @@ EXPLAIN SELECT count(*) FROM measurement WHERE logdate >= DATE '2008-01-01';
query, partition pruning is performed whenever one of the query, partition pruning is performed whenever one of the
execution parameters being used by partition pruning changes. execution parameters being used by partition pruning changes.
Determining if partitions were pruned during this phase requires Determining if partitions were pruned during this phase requires
careful inspection of the <literal>nloops</literal> property in careful inspection of the <literal>loops</literal> property in
the <command>EXPLAIN ANALYZE</command> output. 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> </para>
</listitem> </listitem>
</itemizedlist> </itemizedlist>