[pgpool-general: 1945] Re: pgpool-II 3.3 RC1 released

Andrew Bruce andrew.bruce at hslmobile.com
Fri Jul 26 20:44:59 JST 2013

> Pgpool Global Development Group is pleased to announce the
availability of
> pgpool-II 3.3 RC1. There are some bug fixed and a new feature from

This is good (although I'll need to wait for the official release).

Some questions:
 - Will there (or is there) a guide on how to migrate from 3.2.x to 3.3?

I have a system that's about to go into production, so I'd like to be
able to upgrade with minimal (no) interruption to the database service.

 - Does 3.3 interwork with 3.2.x (I'm currently running 3.2.5)?

My system has two PgPool servers configured for HA using the PgPool
watchdog. My three postgres servers are set up with synchronous
streaming replication. Will I be able to upgrade the standby to 3.3, and
it will interwork with the active PgPool server on 3.2.5. Additionally,
in the event of a failover on the database servers, will PgPool 3.3 be
happy with the PgPool 3.2.5 SQL functions/binaries that are running on
the database servers?

Obviously, I'm looking at interworking over a short period while I
upgrade the entire system, but I would like to be able to perform the
upgrade with zero downtime for the database service.

I would expect that an outline process would be:

1. Shutdown and upgrade the standby PgPool server 'B'
2. Bring up the standby PgPool server 'B' (will it be happy with the
active PgPool Server 'A' running 3.2.5?)
3. Shutdown and upgrade the active PgPool server 'A'  (forcing a
failover to server 'B' running 3.3)
4. Bring up the PgPool server 'A' - it should now come up in standby

The PgPool servers are  now upgraded to 3.3, but we need to upgrade the
SQL functions and related binaries on the postgresql servers:

5. Upgrade the asynchronous slave database server 'Z' (no failover?)
6. Upgrade the synchronous slave database server 'Y' (no failover?)
7. Upgrade the primary database server 'X' (no failover?)

At any of these junctures, if there is a database failover triggered for
whatever reason, I would need PgPool 3.3 to interwork with PgPool 3.2.x
without issue. 

Obviously, when PgPool Server 'B' is upgraded, and it starts PgPool 3.3,
it must be able to interwork with the 'active' PgPool Server 'A' still
on 3.2.x. I'm aware that there are changes to the watchdog in 3.3. Does
this break the interworking in HA mode?

Also, when PgPool Server 'A' is shutdown for upgrading, there will be a
PgPool failover that must also work - Server 'B' on 3.3 must detect that
Server 'A' on 3.2.x has gone, and must take over the VIP address,

I'd be very interested in your feedback.

Kind regards,

Andy Bruce

More information about the pgpool-general mailing list