Re: Hardware/OS recommendations for large databases (

Tom Lane <tgl@sss.pgh.pa.us> writes:

> Greg Stark <gsstark@mit.edu> writes:
> > Last I heard the reason count(*) was so expensive was because its state
> > variable was a bigint. That means it doesn't fit in a Datum and has to be
> > alloced and stored as a pointer. And because of the Aggregate API that means
> > it has to be allocated and freed for every tuple processed.
>
> There's a hack in 8.1 to avoid the palloc overhead (courtesy of Neil
> Conway IIRC).

ah, cool, missed that.

--
greg