Index access much slower than expected.
From: Kenneth Naim <kennethnaim_at_gmail.com>
Date: Thu, 19 May 2011 12:28:26 -0400
Message-ID: <014101cc1641$c8ad2ee0$5a078ca0$_at_gmail.com>
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.
Date: Thu, 19 May 2011 12:28:26 -0400
Message-ID: <014101cc1641$c8ad2ee0$5a078ca0$_at_gmail.com>
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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