Re: Connections hang indefinitely while taking a gin index's LWLock buffer_content lock

Hi!

> 12 дек. 2018 г., в 3:26, Alexander Korotkov <aekorotkov(at)gmail(dot)com> написал(а):
>
> BTW, I still can't see you're setting deleteXid field of
> ginxlogDeletePage struct anywhere.
Oops. Fixed.
>
> Also, I note that protection against re-usage of recently deleted
> pages is implemented differently than it is in B-tree.
> 1) You check TransactionIdPrecedes(GinPageGetDeleteXid(page),
> RecentGlobalDataXmin)), while B-tree checks
> TransactionIdPrecedes(opaque->btpo.xact, RecentGlobalXmin). Could you
> clarify why do we use RecentGlobalDataXmin instead of RecentGlobalXmin
> here?
As far as I understand RecentGlobalDataXmin may be slightly farther than RecentGlobalXmin in case when replication_slot_catalog_xmin is holding RecentGlobalXmin. And GIN is never used by catalog tables. But let's use RecentGlobalXmin like in B-tree.

> 2) B-tree checks this condition both before putting page into FSM and
> after getting page from FSM. You're checking only after getting page
> from FSM. Approach of B-tree looks better for me. It's seems more
> consistent when FSM pages are really free for usage.
Fixed.

Best regards, Andrey Borodin.