From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: pg15.3: dereference null *plan in CachedPlanIsSimplyValid/plpgsql
Date: Thu, 20 Jul 2023 11:55:32 -0400
Message-ID: <584104.1689868532@sss.pgh.pa.us> (raw)
In-Reply-To: <ZLlV+STFz1l/WhAQ@telsasoft.com>
References: <ZLlV+STFz1l/WhAQ@telsasoft.com>
Justin Pryzby <pryzby@telsasoft.com> writes:
> A production instance crashed like so.
Oh, interesting. Apparently we got past the "Has cache invalidation fired
on this plan?" check:
if (!plansource->is_valid || plan != plansource->gplan || !plan->is_valid)
return false;
because "plan" and "plansource->gplan" were *both* null, which is
a case the code wasn't expecting. plansource.c seems to be paranoid
about gplan possibly being null everywhere else but here :-(
> Note that the prior query seems to have timed out in the same / similar plpgsql
> statement:
Hm. Perhaps that helps explain how we got into this state. It must
be some weird race condition, given the lack of prior reports.
Anyway, adding a check for plan not being null seems like the
obvious fix.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, pryzby@telsasoft.com, pgsql-hackers@lists.postgresql.org
Subject: Re: pg15.3: dereference null *plan in CachedPlanIsSimplyValid/plpgsql
In-Reply-To: <584104.1689868532@sss.pgh.pa.us>
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