Re: Memory leak from ExecutorState context?

From: Jehan-Guillaume de Rorthais <jgdr(at)dalibo(dot)com>
To: Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com>
Cc: pgsql-hackers(at)lists(dot)postgresql(dot)org
Subject: Re: Memory leak from ExecutorState context?
Date: 2023-03-01 21:45:58
Message-ID: 20230301224558.1cde4032@karst
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On Wed, 1 Mar 2023 20:34:08 +0100
Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com> wrote:

> On 3/1/23 19:09, Jehan-Guillaume de Rorthais wrote:
> > On Wed, 1 Mar 2023 18:48:40 +0100
> > Jehan-Guillaume de Rorthais <jgdr(at)dalibo(dot)com> wrote:
> > ...
> >> You'll find some intermediate stats I already collected in attachment:
> >>
> >> * break 1, 2 and 3 are from AllocSetAlloc, break 4 is from AllocSetFree.
> >> * most of the non-free'd chunk are allocated since the very beginning,
> >> before the 5000's allocation call for almost 1M call so far.
> >> * 3754 of them have a chunk->size of 0
> >> * it seems there's some buggy stats or data:
> >> # this one actually really comes from the gdb log
> >> 0x38a77b8: break=3 num=191 sz=4711441762604810240 (weird sz)
> >> # this one might be a bug in my script
> >> 0x2: break=2 num=945346 sz=2 (weird
> >> address)
> >> * ignoring the weird size requested during the 191st call, the total amount
> >> of non free'd memory is currently 5488MB
> >
> > I forgot one stat. I don't know if this is expected, normal or not, but 53
> > chunks has been allocated on an existing address that was not free'd before.
> >
>
> It's likely chunk was freed by repalloc() and not by pfree() directly.
> Or maybe the whole context got destroyed/reset, in which case we don't
> free individual chunks. But that's unlikely for the ExecutorState.

Well, as all breakpoints were conditional on ExecutorState, I suppose this
might be repalloc then.

Regards,

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