Subject Re: [ib-support] optimizer question
Author Ann W. Harrison
At 11:50 AM 5/25/2001 +0700, Sindu wrote:

>Basically Jim said the optimizer is broken, and now we're mostly using
>rule-based. CMIIW. So does it actually help if we calculate the index
>statistics for cost-based optimizer?

Jim tends to paint things in black and white - there's a lot of
cost based logic left in the optimizer.

>Ann, please help me to understand it a bit more. Does backup (gbak) will
>automatically update the statistic? Or should I run "SET STATISTICS INDEX
>..." or "ACTIVATE/DEACTIVATE" after my daily backup?

Backup does not update the index statistics. Restore does, but no
one wants to restore a large database regularly. SET STATISTIC INDEX
is faster than DE/ACTIVATE, but the latter has some additional benefits.
It's not a bad idea to do it once every month or so.


We have answers.