Fsync is on, and I'm using a raid controller with an nv-ram backed
buffer. iostat reports await times around 5ms at normal load.

> Are you running with fsync turned on?
> 
> ______________________________________________________________________
> From: Erik G. Burrows
> Sent: Fri 7/16/2004 8:40 PM
> To: Slony-I Mailing List
> Subject: [Slony1-general] Performance
> 
> 
> I'm using PostgreSQL 7.4.3 and Slony-I 1.0.1 with Intel P4 and Xeon
> machines.
> 
> I have a two-server replication setup, one database, one set, working
> very well, but I have some questions about performance.
> 
> I'm not sure how to get some number like updates per second from
> Slony-I, so to give you an idea of the activity of my system, I turned
> on statement logging on the (otherwise idle) slave server. It's doing
> about 600 statements/min.
> 
> My slon configuration is very standard, I haven't changed the 10 second
> sync interval time, or any other option.
> 
> Since turning on replication, the CPU utilization of my master database
> server has tripled, and doing some analysis on the log file (with
> statement and duration logging turned on) I can see it's the "fetch 100
> from LOG;" statements from Slony-I that are causing the increased load.
> Each fetch takes 5 seconds to complete. At 10 second intervals, that's a
> lot of cycles.
> 
> Doing frequent vacuum/vacuum full/analyze of the Slony-I tables has
> little effect.
> 
> So, my question is: What can I do to reduce load on my master server
> from Slony-I? 
> 
> Thanks,
>   Erik G. Burrows
-- 
Erik G. Burrows - KG6HEA                          www.erikburrows.com
PGP Key: http://www.erikburrows.com/files/erik.erikburrows.com.pgpkey