Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM)

Поиск
Список
Период
Сортировка
От Alvaro Herrera
Тема Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM)
Дата
Msg-id 20170320161202.dytk3ski7f7yldj6@alvherre.pgsql
обсуждение исходный текст
Ответ на Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM)  (Pavan Deolasee <pavan.deolasee@gmail.com>)
Список pgsql-hackers
Pavan Deolasee wrote:
> On Tue, Mar 14, 2017 at 7:17 AM, Alvaro Herrera <alvherre@2ndquadrant.com>
> wrote:

> > I didn't like this comment very much.  But it's not necessary: you have
> > already given relcache responsibility for setting rd_supportswarm.  The
> > only problem seems to be that you set it in RelationGetIndexAttrBitmap
> > instead of RelationGetIndexList, but it's not clear to me why.  I think
> > if the latter function is in charge, then we can trust the flag more
> > than the current situation.
> 
> I looked at this today.  AFAICS we don't have access to rd_amroutine in
> RelationGetIndexList since we don't actually call index_open() in that
> function. Would it be safe to do that? I'll give it a shot, but thought of
> asking here first.

Ah, you're right, we only have the pg_index tuple for the index, not the
pg_am one.  I think one pg_am cache lookup isn't really all that
terrible (though we should ensure that there's no circularity problem in
doing that), but I doubt that going to the trouble of invoking the
amhandler just to figure out if it supports WARM is acceptable.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services



В списке pgsql-hackers по дате отправления:

Предыдущее
От: Rafia Sabih
Дата:
Сообщение: Re: [HACKERS] Partition-wise join for join between (declaratively)partitioned tables
Следующее
От: Robert Haas
Дата:
Сообщение: Re: [HACKERS] Partitioned tables and relfilenode