On Wed, 26 Dec 2007, Guillaume Smet wrote:
It's not checkpointing either as using pgbench-tools, I can see that tps and latency are quite stable during the entire run. Btw, thanks Greg for these nice tools.
I stole the graph idea from Mark Wong's DBT2 code and one of these days I'll credit him appropriately.
Then I decided to perform read-only tests using -S option (pgbench -S -s 100 -c 16 -t 30000 -U postgres bench). And still the same behaviour: shared_buffers=64MB : 20k tps shared_buffers=1024MB : 8k tps
Ah, now this is really interesting, as it rules out all the write components and should be easy to replicate even on a smaller server. As you've already dumped a bunch of time into this the only other thing I would suggest checking is whether the same behavior also happens on 8.2 on your server.
-- * Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
