This essential tool for Postgres architectures is continually improving, and is now available in its new releases. Both are bugfix versions.
For those unfamiliar with the tool, it is a middleware with functionality as a load balancer, pooler* and/or replication system for PostgreSQL databases. The 3.1.x versions are compatible with Postgres 9.x, whose streaming replication feature was pushed to Pgpool developers to take advantage of it. This allows the tool to balance queries without using the pgpool-replication technique.
In the 3.1.3/3.0.7 fixes we have:
- Allow multi statement transactions in master/slave mode: Transactions with BEGIN, since 3.1 were sent to the slaves/standby servers as well. This brings non desirable effects when the transaction contains DELETE/INSERT/UPDATE, due to the fact that standbys cannot execute writable SQL. (3.1.3 fix)
- Important fixes for failover detection and execution. (3.1.3 fix)
- Added m4 files to avoid problems when compiling in older operating systems.
- Fixed hangup on PREPARE errors.
- Fixed memory leak in reset queries.
If you are running 3.1.x against Postgres 9 databases, we strongly recommend you upgrade PgPool due to the fixing in the multi statement feature.
For more information http://www.pgpool.net/mediawiki/index.php/Main_Page
* If you need only a connection pooler for Postgres, I prefer PgBouncer http://wiki.postgresql.org/wiki/PgBouncer. It is lightweight and more specific and simply works, without as much configuration.