"Dann Corbit" <[EMAIL PROTECTED]> 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/ Custom software development, systems and network consulting. Java PostgreSQL Enhydra Python Zope Perl Apache Linux BSD... ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
