RE: Union all very slow.

The explain plan will only reflect what is already known : that there is a full table scan in the access path.
to understand the 'WHY this change' you need to take the 10053.  

bp

From: Dennis Williams [mailto:oracledba.williams_at_gmail.com] Sent: Wednesday, 25 October, 2006 8:40 PM To: Randy.Steiner_at_nyct.com
Cc: oracle-l_at_freelists.org
Subject: Re: Union all very slow.

Randy,  

I'd start by doing an EXPLAIN PLAN on each part and the whole thing. You didn't mention your Oracle version, but maybe the CBO is getting smart enough to optimize the entire query, so is making a bad decision.  

Dennis Williams  

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