On Mar 8, 2007, at 11:51 PM, Greg Smith wrote:
> almost everything that's dirty is also pinned during pgbench, and
> the LRU is lucky to find anything it can write as a result
I'm wondering if pg_bench is a good test of this stuff. ISTM it's
unrealistically write-heavy, which is going to tend to not only put a
lot of dirty buffers into the pool, but also keep them pinned enough
that you can't write them.
Perhaps you should either modify pg_bench to do a lot more selects
out of the various tables or look towards a different benchmark.
--
Jim Nasby jim(at)nasby(dot)net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)