Re: [HACKERS] strange behaviour on pooled alloc (fwd) - Mailing list pgsql-hackers

From jwieck@debis.com (Jan Wieck)
Subject Re: [HACKERS] strange behaviour on pooled alloc (fwd)
Date
Msg-id m109oTs-000EBRC@orion.SAPserv.Hamburg.dsh.de
Whole thread Raw
In response to Re: [HACKERS] strange behaviour on pooled alloc (fwd)  (Vadim Mikheev <vadim@krs.ru>)
List pgsql-hackers
>
> Jan Wieck wrote:
> >
> >     I have modified ExecutorStart() so it makes it's private copy
> >     of the actual  QuerySnapshot  in  it's  own  executor  memory
> >     context. Could you please comment if what is in QuerySnapshot
> >     at the time of ExecutorStart() get's or should  get  modified
> >     anywhere  during  the  execution of a plan. The name snapshot
> >     tells me NOT. But you're the one to judge.
>
> You're correct. Alternativly, we could use some refcount
> in Snapshot structure...

    As  it  is  now,  the snapshot data exists in the same memory
    context as the execution state which isn't free'd  explicitly
    (auto  done  on AllocSetReset() when memory context dies). No
    need to add another bookkeeping that's hard to track.

    So pooled memory allocation is done now.


Jan

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