From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Pengfei Wang <pengfei.wang@gmail.com>
To: pgsql-bugs@lists.postgresql.org
Subject: Re: issue: nbtpage.c,_bt_pagedel may get wrong result
Date: Thu, 23 May 2024 14:13:53 +0300
Message-ID: <6abbe3cf-9763-4b9c-b3c7-0d0fc6e2c685@iki.fi> (raw)
In-Reply-To: <CALsf3S3YU43Km==Faya5MPugPo=GE4-akae8oj6pgw_xEh_cEA@mail.gmail.com>
References: <CALsf3S3YU43Km==Faya5MPugPo=GE4-akae8oj6pgw_xEh_cEA@mail.gmail.com>
On 23/05/2024 13:06, Pengfei Wang wrote:
> # issue
> https://github.com/postgres/postgres/blob/da32f5c4bca7f3447b869de2afbbfa0b74443d45/src/backend/acces... <https://github.com/postgres/postgres/blob/da32f5c4bca7f3447b869de2afbbfa0b74443d45/src/backend/acces...;
>
> /*
> * To avoid deadlocks, we'd better drop the leaf page lock
> * before going further.
> */
> _bt_unlockbuf(rel, leafbuf);
>
> /*
> * Check that the left sibling of leafbuf (if any) is not
> * marked with INCOMPLETE_SPLIT flag before proceeding
> */
> Assert(leafblkno == scanblkno);
> if (_bt_leftsib_splitflag(rel, leftsib, leafblkno))
> {
> ReleaseBuffer(leafbuf);
> return;
> }
>
> After unlocking leaf, but before call _bt_leftsib_splitflag, leftsib may
> be already split, and leafbuf's current left sibling is in
> INCOMPLETE_SPLIT status.
In that case, there should be a downlink for 'leafbuf' in the parent,
and we're good to proceed, right? See the comments in
_bt_leftsib_splitflag().
--
Heikki Linnakangas
Neon (https://neon.tech)
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To: pgsql-bugs@postgresql.org
Cc: hlinnaka@iki.fi, pengfei.wang@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: issue: nbtpage.c,_bt_pagedel may get wrong result
In-Reply-To: <6abbe3cf-9763-4b9c-b3c7-0d0fc6e2c685@iki.fi>
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