Thanks Bill for the explanation - that really helped me out considerably.
What this showed me was that there were only 1024 buffers configured.
I'm not quite clear as to how this happened as the postgresql.conf files
on both systems have the shared_buffers set to ~50000. However it looks
as though the system start script was passing in -B 1024 to postmaster
which was overriding the postgresql.conf settings.
The really odd thing is that that the db start script is also the same
on both systems, so there some other difference there that I need to
track down. However removing the -B 1024 allowed the settings to revert
to the file specified values.
So now I'm back to using ~50k buffers again and things are running a
little more swiftly, and according to pg_buffercache I'm using 49151 of
them (-:
Thanks again to those who helped me track this down.
David.
--
David Brain - bandwidth.com
dbrain@bandwidth.com