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From: Tom Lane <[email protected]>
To: Andres Freund <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: memory leak in trigger handling (since PG12)
Date: Tue, 23 May 2023 13:28:30 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>

Andres Freund <[email protected]> writes:
> I've wondered about some form of instrumentation to detect such issues
> before.

Yeah.

> Could it help to have a mode where the executor shutdown hook checks how much
> memory is allocated in ExecutorState and warns if its too much?

It'd be very hard to set a limit for what's "too much", since the amount
of stuff created initially will depend on the plan size.  In any case
I think that the important issue is not how much absolute space, but is
there per-row leakage.  I wonder if we could do something involving
checking for continued growth after the first retrieved tuple, or
something like that.

> Random aside: I've been wondering whether it'd be worth introducing an
> in-place representation of Bitmap (e.g. if the low bit is set, the low 63 bits
> are in-place, if unset, it's a pointer).

Why?  Unlike Lists, those things are already a single palloc chunk.

			regards, tom lane






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