Gregory Stark wrote:
"Heikki Linnakangas" <[EMAIL PROTECTED]> writes:
Yes, at least for now. I can't believe the patch actually hurts performance,
but I'm not going to spend time investigating it.
Isn't this exactly what you would expect? It will clean up more tuples so
it'll dirty more pages. Especially given the pessimal way vacuum's dirty
buffers are handled until Simon's patch to fix that goes in.
Hmm. Yeah, maybe it'll get better when we get that fixed..
The benefit of the patch that we would expect to see is that you won't need to
run VACUUM as often. In the long term we would expect the stock table to grow
less too but I doubt these tests were long enough to demonstrate that effect.
The size did reach a steady state about half-way through the test, see
the logs here:
patched
http://community.enterprisedb.com/oldestxmin/92/server/relsizes.log
unpatched
http://community.enterprisedb.com/oldestxmin/93/server/relsizes.log
The test was a success in that sense, the patch did reduce the steady
state size of the stock table.
Maybe we would see a gain in transactions per minute or response times
if we traded off the smaller table size to run vacuum slightly less
frequently.. But as I said I don't want to spend time running more tests
for what seems like a small benefit.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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