Re: 7.4b1 vs 7.3.4 performance

Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
>> "P.J. \"Josh\" Rovero" <rovero(at)sonalysts(dot)com> writes:
>>> 7.4b1 is significantly faster (i.e., the higher curve)
>>> over this range of clients and transactions.

> I wonder why pgbench is _so_ much faster on 7.4. I can't think of
> anything that would make that large an improvement.

I was wondering that too. I don't think any of the optimizer work I did
for 7.4 would have the slightest impact on pgbench, because its queries
are so simple. I don't see anything else in the HISTORY file that looks
very promising either. Perhaps it's just the cumulative result of small
tweaks like optimizing palloc0() and using bitmap sets in the planner.

We should try profiling pgbench runs to learn more...

regards, tom lane