RE: Rebuild Index?

From: Mark W. Farnham <>
Date: Fri, 28 Feb 2014 07:52:47 -0500
Message-ID: <1f6701cf3483$fc275530$f475ff90$>


-----Original Message-----

From: [] On Behalf Of Jonathan Lewis
Sent: Friday, February 28, 2014 7:36 AM
To:; Subject: RE: Rebuild Index?

It's not often that you would expect an index to be larger than the underlying table - and when it is it's possible that it should be an index organized table anyway; so your colleague has an informal argument for why an index rebuild in this case might be appropriate. I would work out how big the index ought to be given its data content before doing the rebuild, though; then monitor for time lost on things like "TX enq: index contention" and "buffer busy wait" waits. It's also important to figure out WHY the index has grown larger than necessary and see if you can work out a method for avoiding the growth

If you want some code to check "reasonable size" for an index, then check my blog:

Jonathan Lewis

From: [] on behalf of Karth Panchan [] Sent: 28 February 2014 12:14
Subject: Rebuild Index?


We have table with lot of insert/update/delete every day. High OLTP application in 11g R2 on Linux.

To gain performance my teammate recommend Rebuild index.

His assumption Index size should be less than table size. Other wise we need to rebuild index.

Is that correct? Want get your thoughts.

I am skeptic after Reading Asktom and Jonathan Lewis blog. Both of them claim need good metrics and it is last option.




-- Received on Fri Feb 28 2014 - 13:52:47 CET

Original text of this message