Re: query_rewrite_enabled parameter

From: <fitzjarrell_at_cox.net>
Date: Thu, 14 Jun 2007 11:30:08 -0700
Message-ID: <1181845808.966948.162300@d30g2000prg.googlegroups.com>

On Jun 14, 1:10 pm, zigzag..._at_yahoo.com wrote:
> I am not using function based indexes or materialized views. If I set
> this parameter=FALSE, will cost optimzer do something?. What are the
> advantages of setting this parameter Query_rewtite_enabled=TRUE.

Give us the release of Oracle you're using and we can tell you. I can tell you that from 8.1.6 onwards query_rewrite_enabled is no longer necessary when using function-based indexes. From 8.1.6 through 9.2.0.8 setting that parameter to TRUE changes the rules for transitive closure (this is fixed in 10g) causing the estimated cardinality for affected queries, and thus the execution plans, to be incorrect.

Post the release of Oracle you're using, to four numbers (8i, 9i, 10g are not proper responses). You'll get an accurate answer after you do so.

David Fitzjarrell Received on Thu Jun 14 2007 - 13:30:08 CDT