Re: SeqScan costs

On Aug 18, 2008, at 11:49 AM, Tom Lane wrote:
>> Perhaps what's also needed here is to measure just how accurate
>> the cpu_*
>> costs are. Perhaps they need to be raised somewhat if we're
>> underestimating
>> the cost of digging through 200 tuples on a heap page and the
>> benefit of a
>> binary search on the index tuples.
>
> Possibly. I doubt anyone's ever taken a hard look at the cpu_xxx
> values.

Josh Berkus indicated at PGCon that he's had luck *decreasing* the
CPU costs, but IIRC that was mostly on OLAP systems. It seems we need
some real data here.
--
Decibel!, aka Jim C. Nasby, Database Architect decibel(at)decibel(dot)org
Give your computer some brain candy! www.distributed.net Team #1828