Re: Temporary space needed to create a constraint
Date: Wed, 11 Jul 2012 14:55:12 +0100
Message-ID: <F4EF07685D144B62A3D756800D525E4C_at_Primary>
Alternatively you could set up a temporary "rewrite equivalence" between the statement and something like
select null,null,null,null from dual where 1 = 0
(you might need to include some explicit coercion on the nulls)
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com/all_postings
Author: Oracle Core (Apress 2011)
http://www.apress.com/9781430239543
- Original Message ----- From: "Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> To: "oracle-l" <oracle-l_at_freelists.org> Sent: Wednesday, July 11, 2012 2:52 PM Subject: Re: Temporary space needed to create a constraint
When in doubt, try it out.
Oracle's been doing this since at least 8.1.7.4
Looking at the SQL (which has improved a little since 8.1.7.4) I think it's trying to collect all rows that break the constraint in anticipation of writing them into the exceptions table - should you choose to specify an exceptions table. The nasty bit happens even if you add with novalidate and then validate.
I think you could try capturing the SQL for the check, then creating an SQL Baseline for it that forces it to take a path which would basically be a nested loop on an index full scan. Ideally you do this with a sort group by clause first so that no data is ever found and the second step of the loop never happens. (That's based on a quick inspection of the code - I don't guaranteed at the moment that there is such a legal path.)
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com/all_postings
Author: Oracle Core (Apress 2011)
http://www.apress.com/9781430239543
- Original Message ----- From: "Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> To: "oracle-l" <oracle-l_at_freelists.org> Sent: Wednesday, July 11, 2012 12:39 PM Subject: Re: Temporary space needed to create a constraint
What's your code to define the constraint and the existing index, and what's the execution plan you're seeing in the trace file ? And is the original table a simple heap table, or is it partitioned, and if partitioned was the index local or global ?
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Received on Wed Jul 11 2012 - 08:55:12 CDT