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UNION ALL destroys performance

chuckersMar 14 2009 — edited Mar 19 2009
Strangely, we have 2 queries, which when they run independently, run pretty fast (2 seconds for one, instantaneous for the other), but when they're concatenated into a UNION ALL query with no ORDER BY clause, it takes 45 seconds for it to run.

We tried pushing the SQL into a WITH clause, and some other subquery rewrites, but no perfomance boost. Has anyone seen this before?

version 10.1.0.4
--=Chuck
This post has been answered by 21205 on Mar 16 2009
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Locked on Apr 16 2009
Added on Mar 14 2009
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