[Pgpool-general] Basics of replication with pgpool-II - how does it work? compared to Slony? to Postgres log shipping?

[Aleksey Tsalolikhin]

Hi.   We want to have redundancy for our database;
is pgpool-II the right tool, with it's replication mode?

We want to have 2 database servers, and if one
dies, our application just goes on using the other
one, while we repair the broken one.

Can pgpool-II replicate writes such that if a write
query is submitted, pgpool-II will write it to DB server
A and DB server B, and will only return a success
to the client if both writes succeeded?  otherwise
it will return a failure, perform any necessary rollback
if the write was replicated only to one server?

If that's not how pgpool-II replication works, how does
it work?  I've looked at the manual but I still don't
understand.

I'm familiar with replication with Postgres 8 log shipping
(warm standby),  Postgres 9 streaming replication
(hot standby), and Slony (hot standby).  How does
Pgpool-II replication work and how does it compare to
the Postgres/Slony replication?

Thanks very much,
Aleksey