2007/7/21, Tom Lane <[EMAIL PROTECTED]>:
"Pavel Stehule" <[EMAIL PROTECTED]> writes:
> I was little bit surprised. Is any reason for it?

Are you sure you're comparing apples to apples?  In particular the
default autovacuuming setup is entirely different.  With autovac off
I see 8.3 as faster than 8.2 in pgbench.

I am not sure. But this (or similar) test will do more persons, and
the difference  have to be explained.

Also, remember a couple rules of thumb for choosing pgbench parameters:
keep -c less than the -s scale factor you used for pgbench -i (otherwise
you're mostly measuring update contention, because there are only -s
different rows in the branches table); and use -t at least 1000 or so
(otherwise startup transients are significant).

Ok, I have to do more tests.

Note to all: we ***HAVE TO*** settle on some reasonable default
vacuum_cost_delay settings before we can ship 8.3.  With no cost delay
and two or three workers active, 8.3's autovac does indeed send
performance into the tank.

Thank you for reply

Pavel Stehule

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