| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Fábio Moreira <fabio(at)dias(dot)moreira(dot)nom(dot)br> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: Inspecting generated PlannerInfo |
| Date: | 2016-03-03 15:42:53 |
| Message-ID: | 18571.1457019773@sss.pgh.pa.us |
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| Lists: | pgsql-novice |
=?UTF-8?Q?F=C3=A1bio_Moreira?= <fabio(at)dias(dot)moreira(dot)nom(dot)br> writes:
> From what I could find, PostgreSQLs tests check for output correctness but
> not if the query planner is actually applying specific optimizations to the
> input query; is that correct?
There are quite a few regression tests that look at EXPLAIN output to
verify that particular optimizations happen (or not) as intended.
There's no user-facing mechanism other than that. For development
purposes, you could consider inserting pprint() calls on Paths at
critical points, or just invoking pprint manually from gdb --- the latter
is what I usually do.
regards, tom lane
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