Re: slight tweaks to documentation about runtime pruning
Amit Langote <amitlangote09@gmail.com>
From: Amit Langote <amitlangote09@gmail.com>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-12-09T15:57:39Z
Lists: pgsql-hackers
On Sun, Dec 9, 2018 at 8:13 PM David Rowley <david.rowley@2ndquadrant.com> wrote: > listp1 was scanned twice (loops=2), listp2 was scanned just once. > > Now it is true that if the subplan was executed 0 times that it will > appear as "(never executed)", but do we really need to explain in this > area that "(never executed)" means loops=0? Ah, I see what you mean. So, "(never executed)" is not the only sign of of run-time pruning occurring. The value of loops can be different for different subplans / partitions, and it being lower for a given subplan means that the subplan has been pruned more number of times. Thanks, Amit
Commits
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Clarify runtime pruning in EXPLAIN
- 1e6240a3fe91 12.0 landed
- f760a8b5cc1f 11.2 landed