Subject: Re: BUG #17844: Memory consumption for memoize node
To: David Rowley <dgrowleyml@gmail.com>, pgsql-bugs@lists.postgresql.org
References: <17844-d2f6f9e75a622bed@postgresql.org>
 <CAApHDvpvfmgkSxTG-3+kVTFdVtbb+_s0ta4qz+6ovXZQqqtRWQ@mail.gmail.com>
 <CAApHDvqGErGuyBfQvBQrTCHDbzLTqoiW=_G9sOzeFxWEc_7auA@mail.gmail.com>
From: Alexey Ermakov <alexey.ermakov@dataegret.com>
Message-ID: <bccbeb7e-e945-6aa8-7610-7df1057d774a@dataegret.com>
Date: Mon, 20 Mar 2023 12:23:11 +0600
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On 2023-03-19 15:33, David Rowley wrote:
> On Sat, 18 Mar 2023 at 13:22, David Rowley <dgrowleyml@gmail.com> wrote:
>> It seems to be related to a bug in nodeMemoize.c where we're
>> evaluating the cache key expressions in the ExecutorState context. We
>> should really be in a more temporary context that gets reset early in
>> cache_lookup() before the call to prepare_probe_slot(). I'll need to
>> look in a bit more detail about what that context actually should be.
> I've attached fix_memoize_memory_leak.patch to address this.
>
> Using your test case, here are the memory stats before and after the
> fix (taken during ExecEndMemoize).
>
Thanks a lot! Could you please point me in the direction how to get such 
memory stats ? I might know another memory leak I'd like to check but 
sadly I don't know right tools to measure memory usage.


--

Thanks,

Alexey Ermakov