Re: How frequently: Analysing

From: Holger Baer <holger.baer_at_science-computing.de>
Date: Fri, 21 Feb 2003 11:58:45 +0100
Message-ID: <3E560665.8010107@science-computing.de>

On asktom.oracle.com there was a thread where this was also answered:

http://asktom.oracle.com/pls/ask/f?p=4950:8:17279331821445557::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:2202891332282,

Although I agree in general with Howard's post, there was a slight different explanation from Tom Kyte. Basically the effect of analyzing the data dictionary is so bad because it's only going to be partially analyzed due to deadlocks. And this will trip CBO completely over.

And in some Oracle Versions this can even get worse, because some of the views contained hints which forced the cbo when stats where found... (with really terrible results).

More worse, in 8.1.7 dbms_stats seemed to contain an error where dbms_stats.gather_database_stats would lead to a partially analyzed sys schema.

Regards,

Holger Received on Fri Feb 21 2003 - 04:58:45 CST

Re: How frequently: Analysing - question added