Re: [Fwd: FAQ update about transaction interleaving]

I think that the preferred format for FAQ updates is as a patch to the

www project's src/documentation/content/xdocs/documentation/faq.xml file
from CVS.

-- Mark

On Fri, 2006-11-10 at 12:33 +0000, Heikki Linnakangas wrote:
> I posted this some time ago, but no-one reacted, so I'm reposting...
>
> Is there a preferred format for FAQ updates?
>
> -------- Original Message --------
> From: Heikki Linnakangas <heikki@enterprisedb.com>
> To: pgsql-jdbc@postgresql.org
> Date: Fri, 29 Sep 2006 16:34:11 +0100
> Subject: FAQ update about transaction interleaving
>
> Our FAQ entry on XA support is quite vague; most users don't know what
> transaction interleaving is or why they should care.
>
> Here's an updated version based on a response I gave earlier to a post
> asking about it:
>
> -----------------
> 1.1. Does the driver have XA support?
>
> Yes, starting with the 8.1dev-403 driver. However, the transaction
> interleaving is not supported.
>
> 1.2. What is "transaction interleaving"?
>
> Transaction interleaving means that one database connection can be used
> for multiple transactions at the same time, switching between the
> transactions.
>
> Transaction interleaving is mostly useless, but it's a required part of
> the JTA specification. Some application servers use it to allow a bit
> more concurrency without allocating a bigger jdbc connection pool.
>
> Few JDBC drivers support transaction interleaving properly. Some fake it
> by issuing early prepare commands, risking transaction integrity, some
> give strange error messages, some fail in other, subtle ways. The
> PostgreSQL JDBC driver does it's best to detect interleaving and throws
> a proper error message when it can't do what's requested.
>
> Because of the lack of driver support, all of the popular application
> servers use provide options to work around it, or don't use it at all.
> Therefore, lack of transaction interleaving shouldn't affect your
> application or data integrity.
>
> See the JTA specification, section 3.4.4, or search the pgsql-jdbc
> mailing list archives for more information.
>
> 1.3. How to configure application server XXX to work with the PostgreSQL
> JDBC driver
>
> [We need some examples...]
>
> Please read the documentation of your application server for details.
> You might need to set a flag to disable transaction interleaving. In
> JBoss, for example, set the "track-connection-by-tx" parameter.
>
>