Re: cost based optimization-Reposted

From: Neilc <neilc-olops_at_btinternet.com>
Date: Tue, 7 Sep 1999 10:56:31 +0100
Message-ID: <7r2njq$7sn$1@pheidippides.axion.bt.co.uk>

Hi,
>> 1.Does the cost based optimization work on those sql queries which dont
>> have hints specified in them.?

Depends, if the init.ora setting OPTIMIZER_MODE is set to CHOOSE or ALL_ROWS or FIRST ROWS, and the tables or indexes have statistics against them (i.e they have been analyzed) then yes the CBO will be used.

>> 2. How frequently should the tables be analysed.

Again it depends on how often the tbales change in terms of inserts, updates and deletes against them, however once a week is not uncommon.

>> Any help will be greatly appreciated>
Received on Tue Sep 07 1999 - 04:56:31 CDT