Re: PgPool changes WAS: PostgreSQL clustering VS MySQL clustering

Tatsuo,

> > Depends on your connection pooling software, I suppose.  Most connection
> > pooling software only returns connections to the pool after a user has
> > been inactive for some period ... generally more than 3 seconds.  So
> > connection continuity could be trusted.
>
> Not sure what you mean by "most connection pooling software", but I'm
> sure that pgpool behaves differently.

Ah, clarity problem here.    I'm talking about connection pooling tools from
the client (webserver) side, such as Apache::DBI, PHP's pg_pconnect,
Jakarta's connection pools, etc.   Not pooling on the database server side,
which is what pgPool provides.

Most of these tools allocate a database connection to an HTTP/middleware
client, and only release it after a specific period of inactivity.    This
means that you *could* count on "web-user==connection" for purposes of
switching back and forth to the master -- as long as the connection-recycling
timeout were set higher than the pgPool switch-off period.

--
Josh Berkus
Aglio Database Solutions
San Francisco