Re: PostgreSQL and PHP persistent connections

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Peter Mount <peter(at)retep(dot)org(dot)uk>
Cc: "Thies C(dot) Arntzen" <thies(at)digicol(dot)de>, pgsql-jdbc(at)postgresql(dot)org, PostgreSQL-interfaces <pgsql-interfaces(at)postgresql(dot)org>
Subject: Re: PostgreSQL and PHP persistent connections
Date: 2001-03-19 22:01:26
Message-ID: 200103192201.RAA05090@candle.pha.pa.us
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> At 14:12 07/02/01 -0500, Bruce Momjian wrote:
> >Thies, we talked at LinuxWorld about improving the reliability of
> >persistent PostgreSQL connections in PHP.
> >
> >I believe the problem is that persistent connections sometime do not
> >pass clean sessions because of open transactions and SET changes to the
> >session.
> >
> >We discussed using 'ROLLBACK' before passing a connection to a new user,
> >but the problem was that ROLLBACK with no open transaction causes a
> >server log error message. We discussed adding 'ROLLBACK SILENT' to fix
> >this, but I believe a better, more portable solution is a simple "BEGIN
> >WORK;ROLLBACK". This will do nothing if there is no open transaction,
> >and will ROLLBACK any open transaction. I propose this be sent by PHP
> >as the first query when passing persistent connections.
> >
> >As far as SET changes, does anyone on the PostgreSQL interfaces list
> >have a suggestion on how to RESET all session parameters? Seems we may
> >need to add this feature in to the backend.
>
> Some Java apps utilise connection pools so they would possibly benefit. I
> could add the BEGIN WORK;ROLLBACK; to JDBC.

I don't think that belongs in jdbc. It is the connection pooling code
that should execute those statements before passing over a new
connection. No reason to have it for all jdbc users.

--
Bruce Momjian | http://candle.pha.pa.us
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