Re: Index access much slower than expected.
- From: David Fitzjarrell <oratune@xxxxxxxxx>
- To: kennethnaim@xxxxxxxxx, oracle-l@xxxxxxxxxxxxx
- Date: Thu, 19 May 2011 09:39:37 -0700 (PDT)
Can you post the original plan?
David Fitzjarrell
________________________________
From: Kenneth Naim <kennethnaim@xxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx
Sent: Thu, May 19, 2011 9:28:26 AM
Subject: Index access much slower than expected.
I have an application generated 4 table query that produced explain plan that
has an index join of 3 indexes (hash join of 2 indexes hash joined to a third)
among the other joins. The 3 indexes are on the same table mdp, it has 55k rows
and is 88mb in size, 309 columns, 1200 chained rows.
The query ran for 9+ minutes with the index joins. With a full hint it runs
1:40. I altered the session to disable index joins using the underscore
parameter and got an identical plan to the original with just one of the
indexes. I expected this to be perform better than the full scan as the
predicate returns 2305 rows out of the 55k or 4% however it ran for over 10
minutes. Any ideas on what I should be looking at to figure out why this is
happening?
Thanks,
Ken
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