"Dann Corbit" <DCorbit@connx.com> writes:
> It would be nice if total table cardinality could be maintained live.
> So (after the initial vacuum) we update the cardinality for each table
> in the system table (or perhaps add an entry to the table itself).
> There are two reasons why this is an important optimization. Firstly,
> it is a psychological benefit for both benchmarks and customers when
> doing a select count(*) from <tablename>. This is something that pops
> up all the time in benchmarks and customers do it too, in order to get a
> feel for speed. By storing the current number and incrementing for
> every insert and decrementing for every delete, the count(*) case with
> no where clause can return the value instantly.
How would this work with MVCC?
-Doug
--
Doug McNaught Wireboard Industries http://www.wireboard.com/
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