[Pgpool-general] 2PC (was: Re: PGPool suggestion)

[Tatsuo Ishii]

> Another question I have: will pgpool use the new pg 8.1 two phase commit
> to implement loadbalancing/replication?
> 
> Am I missing anything when I'm saying this would make for a really robust
> loadbalancing solution with changes going to all servers?
> Or are there troubles going with this approach?

I'm not sure if 2PC does anything good for replication.

Suppose master succeeds with a transaction while secondary does
not. You might say "2PC allows master rollback the pre committed
transaction". However, this already has suggested that either 1)
contents of master/secondary differ or 2) hardware, network OS or
whatever has been broken on secondary. In this case it seems more safe
to detach secondary and goes into the degeration mode than keeping
replication with inconsistent DB contents or broken hardware.

What do you think?
--
SRA OSS, Inc. Japan
Tatsuo Ishii