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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Sami Imseih <samimseih@gmail.com>
Cc: Andrei Lepikhov <lepihov@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: Greg Sabino Mullane <htamfids@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Cc: Nikolay Samokhvalov <nik@postgres.ai>
Cc: Ilia Evdokimov <ilya.evdokimov@tantorlabs.com>
Subject: Re: track generic and custom plans in pg_stat_statements
Date: Thu, 24 Jul 2025 13:43:47 -0400
Message-ID: <1673684.1753379027@sss.pgh.pa.us> (raw)
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Sami Imseih <samimseih@gmail.com> writes:
>> That is not to say that I think 719dcf3c4 was a good idea: it looks
>> rather useless from here.  It seems to me that the right place to
>> accumulate these sorts of stats is in CachedPlanSources, and I don't
>> see how this helps.  What likely *would* help is some hooks in
>> plancache.c for pg_stat_statements to connect into so it can count

> One possible hook for accumulating custom and generic plans per
> queryId would be inside GetCachedPlan. However, this would require
> calling pgss_store an extra time, in addition to ExecutorEnd, every time
> GetCachedPlan is executed, which could introduce non-negligible
> overhead.

Only if you insist that the way to handle this is to call pgss_store
at that time.  I'd be inclined to think about having some transient
process-local data structure that can remember the info until
ExecutorEnd.  But the plan tree is not the right place, because of
the circularity problem.

			regards, tom lane





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  Cc: tgl@sss.pgh.pa.us, samimseih@gmail.com, lepihov@gmail.com, michael@paquier.xyz, htamfids@gmail.com, nik@postgres.ai, ilya.evdokimov@tantorlabs.com
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