Re: cache in plpgsql - Mailing list pgsql-hackers

may be postgres can use same way like triggers working,
and when relation is droping ( what is equal to delete from pg_class)
there could be something like trigger after .. which can
waiting for CREATE or DROP command, and then clean-up cache,
(for each backend).
This could be for example same message, not just trigger
(i said trigger only to show scheme of acction)

ehheh this idea is also wrong ?

On Wed, 31 Dec 2003, Jan Wieck wrote:

> ivan wrote:
> > why all backend can not using one cache, which would be always
>
> Variable sized shared memory with garbage collection for SPI plans?
>
> > in real state ... or i can just clear only my cache, at first
> > (if i know that this relation could has another oid)
> > and then normal using relations ?
>
> As said, that is not sufficient. The user who does the DDL statement can
> as well reconnect to the database to recompile all saved plans. It is
> the 200 persistent PHP DB connections that suffer from not finding the
> index any more.
>
> >
> > or ... just turn off cache, because its strange to has possible
> > using drop, create etc in function, but using only EXECUTE ..
>
> Do you have any numbers about how that would affect performance?
>
>
> Jan
>
> >
> > there must be same solution .. no ?
> >
> >
> > On Wed, 31 Dec 2003, Jan Wieck wrote:
> >
> >> ivan wrote:
> >>
> >> >as new know plpgsql has special cache which remember too long (event
> >> >non-existing tables (i mean old oid)) so i suggest to create same function
> >> >only in plpgsql which would clear this cache, or sth like this ?
> >> >
> >> >for ie, where i drop table i would do plpgsql_clear_cache ();
> >> >and when i will create one more time table with this same name plpgsql
> >> >will not remeber wrong oid
> >> >
> >> >possible ?
> >> >
> >> >
> >>
> >> You obviously did not bother to search the archives on this.
> >>
> >> This will not solve the problem since the "cache" you're talking about
> >> is per backend local memory. So if one backend modifies the schema, how
> >> does it cause all other to forgt? Since the same problem exists in
> >> general for everything that uses SPI, the solution lies in there.
> >>
> >>
> >> Jan
> >>
> >> --
> >>
> >> #======================================================================#
> >> # It's easier to get forgiveness for being wrong than for being right. #
> >> # Let's break this rule - forgive me.                                  #
> >> #================================================== JanWieck@Yahoo.com #
> >>
> >>
> >>
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>
> --
> #======================================================================#
> # It's easier to get forgiveness for being wrong than for being right. #
> # Let's break this rule - forgive me.                                  #
> #================================================== JanWieck@Yahoo.com #
>