Re: Good News re count(*) in 8.1

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:

> There have been several times that I have run a SELECT COUNT(*) on an entire
> table on all central machines. On identical hardware, with identical data,
> and equivalent query loads, the PostgreSQL databases have responded with a
> count in 50% to 70% of the time of the commercial product, in spite of the
> fact that the commercial product does a scan of a non-clustered index while
> PostgreSQL scans the data pages.

I take it these are fairly narrow rows? The big benefit of index-only scans
come in when you're scanning extremely wide tables, often counting rows
matching some indexed criteria.

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greg