(The example is really count(pkey) because count(*) is always going to do a seq scan I reckon - and could probably never use an index).
postgres knows that count(*) is just "count the rows", you can use count(1), it makes no difference...
Alex Turner NetEconomist
On Fri, 07 Jan 2005 11:17:32 -0700, Scott Ribe <[EMAIL PROTECTED]> wrote:> I guess what I"m really asking is why can't you run aggregates over an index?
It's got to do with MVCC and transaction consistency. Running count(*) or an
aggregate function on an index could include records that should not be
visible to your current transaction.
-- Scott Ribe [EMAIL PROTECTED] http://www.killerbytes.com/ (303) 665-7007 voice
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