Re: Caching of Queries - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: Caching of Queries
Date
Msg-id 200410130102.i9D12vN08023@candle.pha.pa.us
Whole thread Raw
In response to Re: Caching of Queries  (Tatsuo Ishii <t-ishii@sra.co.jp>)
List pgsql-performance
Added to TODO:

* Add RESET CONNECTION command to reset all session state

  This would include resetting of all variables (RESET ALL), dropping of
  all temporary tables, removal of any NOTIFYs, etc.  This could be used
  for connection pooling.  We could also change RESET ALL to have this
  functionality.


---------------------------------------------------------------------------

Tatsuo Ishii wrote:
> > Tatsuo Ishii <t-ishii@sra.co.jp> writes:
> > > First, it's not a particular problem with pgpool. As far as I know any
> > > connection pool solution has exactly the same problem. Second, it's
> > > easy to fix if PostgreSQL provides a functionarity such as:"drop all
> > > temporary tables if any".
> >
> > I don't like that definition exactly --- it would mean that every time
> > we add more backend-local state, we expect client drivers to know to
> > issue the right incantation to reset that kind of state.
> >
> > I'm thinking we need to invent a command like "RESET CONNECTION" that
> > resets GUC variables, drops temp tables, forgets active NOTIFYs, and
> > generally does whatever else needs to be done to make the session state
> > appear virgin.  When we add more such state, we can fix it inside the
> > backend without bothering clients.
>
> Great. It's much better than I propose.
>
> > I now realize that our "RESET ALL" command for GUC variables was not
> > fully thought out.  We could possibly redefine it as doing the above,
> > but that might break some applications ...
> >
> >             regards, tom lane
> >
>
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