From: Bruce Momjian <pgman@candle.pha.pa.us>
Message-Id: <200103192201.RAA05090@candle.pha.pa.us>
Subject: Re: PostgreSQL and PHP persistent connections
In-Reply-To: <5.0.2.1.0.20010207214024.009ee160@mail.retep.org.uk>
	"from Peter Mount at Feb 7, 2001 09:41:43 pm"
To: Peter Mount <peter@retep.org.uk>
Date: Mon, 19 Mar 2001 17:01:26 -0500 (EST)
CC: "Thies C. Arntzen" <thies@digicol.de>, pgsql-jdbc@postgresql.org,
	PostgreSQL-interfaces <pgsql-interfaces@postgresql.org>
MIME-Version: 1.0
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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.

-- 
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