[Pgpool-general] Pgpool with many inserts and updates

[Jaume Sabater]

On Wed, Mar 3, 2010 at 2:15 AM, Josh Berkus <josh at agliodbs.com> wrote:

>> Pgpool-II does not enhance write performance of PostgreSQL.  You will
>> get write performance of roughly 60-70% of PostgreSQL when pgpool-II
>> is running in repication mode. With master/slave mode + Slony-I you
>> could obtain better than it, still it is slightly lower than 100%. So
>> first thing you should do is, to prepare good hardwares and to tune
>> PostgreSQL to get enough write performance for your applications.
>
> Wait, we take a 30% hit for pgPool2?  Seems quite large ... the overhead
> for pgPool1 in replication mode was much lower.
>
> What accounts for the overhead?

The fact that it's a synchronous cluster, i.e. writes are committed to
all nodes, then ACK is returned to the client (actually it's firs the
master, then all the slaves, then ACK to the client).

-- 
Jaume Sabater
http://linuxsilo.net/

"Ubi sapientas ibi libertas"