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help / color / mirror / Atom feedFrom: Alexander Korotkov <aekorotkov@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alexander Lakhin <exclusion@gmail.com>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18374: Printing memory contexts on OOM condition might lead to segmentation fault
Date: Wed, 6 Mar 2024 22:24:03 +0200
Message-ID: <CAPpHfduPAmF95Zg=sMfhBW+0Q=Bq2KKzF7AamvTQ0UDm80ZOLA@mail.gmail.com> (raw)
In-Reply-To: <3399097.1709501969@sss.pgh.pa.us>
References: <18374-ebb8113ce4d02f0d@postgresql.org>
<3120721.1709395887@sss.pgh.pa.us>
<b1a1eaf3-d5b7-da52-6bb7-c5b3fbe47f3e@gmail.com>
<3140126.1709405398@sss.pgh.pa.us>
<3148162.1709409519@sss.pgh.pa.us>
<3399097.1709501969@sss.pgh.pa.us>
On Sun, Mar 3, 2024 at 11:39 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I do think it's probably worth reducing MemoryContextDelete's stack
> usage to O(1), just to ensure we can't get into stack trouble during
> transaction abort. That's not hard at all, as attached.
>
> I tried to make MemoryContextResetChildren work similarly, but that
> doesn't work because if we're not removing child contexts then we
> need extra state to tell which ones we've done already. For the
> same reason my idea for bounding the stack space needed by
> MemoryContextStats doesn't seem to work. We could possibly make it
> work if we were willing to add a temporary-use pointer field to all
> MemoryContext headers, but I'm unconvinced that'd be a good tradeoff.
For removing recursion from memory context processing, please check
the patch by Heikki [1], and my slightly revised version [2].
Links.
1. https://www.postgresql.org/message-id/6b48c746-9704-46dc-b9be-01fe4137c824%40iki.fi
2. https://www.postgresql.org/message-id/CAPpHfdtQVzkKgrxqKZE9yESnu7cAATVQbGktVOSXPNWG7GOkhA%40mail.gma...
------
Regards,
Alexander Korotkov
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To: pgsql-bugs@postgresql.org
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Subject: Re: BUG #18374: Printing memory contexts on OOM condition might lead to segmentation fault
In-Reply-To: <CAPpHfduPAmF95Zg=sMfhBW+0Q=Bq2KKzF7AamvTQ0UDm80ZOLA@mail.gmail.com>
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