Re: issue: nbtpage.c,_bt_pagedel may get wrong result
| От | Pengfei Wang |
|---|---|
| Тема | Re: issue: nbtpage.c,_bt_pagedel may get wrong result |
| Дата | |
| Msg-id | CALsf3S0uAtkY8kAVkqxjA6-Z3e3vGJpTm7sBO1a__Gw-quc_gg@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: issue: nbtpage.c,_bt_pagedel may get wrong result (Heikki Linnakangas <hlinnaka@iki.fi>) |
| Список | pgsql-bugs |
Yes, you are right. I've checked _bt_leftsib_splitflag, it checks if the right sibling of 'leftisb' is till leafbuf.
Thank you for your explanation.
On Thu, May 23, 2024 at 7:13 PM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
On 23/05/2024 13:06, Pengfei Wang wrote:
> # issue
> https://github.com/postgres/postgres/blob/da32f5c4bca7f3447b869de2afbbfa0b74443d45/src/backend/access/nbtree/nbtpage.c#L1943 <https://github.com/postgres/postgres/blob/da32f5c4bca7f3447b869de2afbbfa0b74443d45/src/backend/access/nbtree/nbtpage.c#L1943>
>
> /*
> * 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)
Regards
Wang Pengfei
Wang Pengfei
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