Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> RE: Index thrashing still after Alter table move and new buildin g of indexes.

RE: Index thrashing still after Alter table move and new buildin g of indexes.

From: Wolfson Larry - lwolfs <>
Date: Thu, 22 Jul 2004 18:20:19 -0500
Message-ID: <>


	It's not clear what order you did things.
	I don't know about 9.2 rebuilds but on 8.1.6 they definitely deleted
the index stats.
	If there's no stats the optimizer may use the last created date as
the best choice.

        Do you have the plan for this code before and after you rebuilt the indexes?

        That is, is the 10 minute plan the same as the 7 hour plan?

        Did you do another analyze stats after the move and after the recreating the indexes?

-----Original Message-----
[]On Behalf Of Leonard, George Sent: Thursday, July 22, 2004 3:10 PM
To: ''
Cc: Desplace, Laura
Subject: Index thrashing still after Alter table move and new building of indexes.

Hi all

quick question:

Does an alter table xxx move tablespace do a block for block move or does it repack the table.

we are having a problem on physical to logical IO on a specific 2 tables and specific 2 indexes on the tables for a specific update statement.

It seems to be just thrashing/spinning its wheels when using these indexes.

We rebuild the FK indexes on Tuesday morning and this resolved the problem where the update returned to under 10 min, but this morning it said expected to complete time of 7 hours,

we just went thought a process of dropping all constraint and related indexes, moving the 2 tables to new tablespaces and building completely new indexes and it seems this did not fix the problem.

We are wondering if the problem is not maybe actual data related since the analyzes did not return/report any errors.

Oracle version is on Sparc 64, Solaris 2.8 aka 8

Ideas, comments please


George Leonard
Oracle Database Administrator
New Dawn Technologies @ Wesbank  

You Have The Obligation to Inform One Honestly of the risk, And As a Person You Are Committed to Educate Yourself to the Total Risk In Any Activity! Once Informed & Totally Aware of the Risk, Every Fool Has the Right to Kill or Injure Themselves as They See Fit!

-----Original Message-----
From: Niall Litchfield [] Sent: Thursday, July 22, 2004 21:56 PM
Subject: Re: Creating Histograms

Comments as always
On Thu, 22 Jul 2004 10:37:21 -0400, Freeman, Donald <> wrote:
> OK, I understand your point about gathering on schedule. I'm moving into =
> taking over a turn-key contractor developed system. We are doing =
> stats/computed every day. We only add, at most, a few thousand records =
> a day. This is much, much less than 10%. We converted a few million =
> records, about five years worth of records, from four or five other =
> public health databases but our daily accrual is relatively small. I =
> probably wouldn't have to run stats once in a month.

take note of how many records you add to relatively *small* tables. 13 rows added to one of our tables caused hell until we gathered stats again (and it took ages for anyone to admit that anything ahd changed). That would be 13 rows in the sense of another financial year to add to the 2 existing ones - so hardly significant at all :).

I guess I'm saying different objects might have different stats needs.

>We also don't =
> collect system stats. I'm hoping to get enough information here to 'have =
> a meeting' and get all of that changed, the method and rate of =
> collection.

Test system stats carefully (I'm probably too cautious on this), but system stats are likely to make quite a noticeable difference to execution times. It is, I'm increasingly convinced, the *right* thing to do. It doesn't mean that you may not have adverse effects. Overall system stats have been positive for our test financial environmentenough  so that they get introduced with the next software upgrade that is running there - but there has been the odd hiccup.

Niall Litchfield
Oracle DBA
Please see the official ORACLE-L FAQ:
To unsubscribe send email to:
put 'unsubscribe' in the subject line.
Archives are at
FAQ is at


The views expressed in this email are, unless otherwise stated, those of the
author and not those
of the FirstRand Banking Group or its management.  The information in this
e-mail is confidential
and is intended solely for the addressee. Access to this e-mail by anyone
else is unauthorised. 
If you are not the intended recipient, any disclosure, copying, distribution
or any action taken or 
omitted in reliance on this, is prohibited and may be unlawful.
Whilst all reasonable steps are taken to ensure the accuracy and integrity
of information and data 
transmitted electronically and to preserve the confidentiality thereof, no
liability or 
responsibility whatsoever is accepted if information or data is, for
whatever reason, corrupted 
or does not reach its intended destination.

Please see the official ORACLE-L FAQ:
To unsubscribe send email to:
put 'unsubscribe' in the subject line.
Archives are at
FAQ is at

The information contained in this communication is
confidential, is intended only for the use of the recipient
named above, and may be legally privileged.
If the reader of this message is not the intended
recipient, you are hereby notified that any dissemination, 
distribution, or copying of this communication is strictly
If you have received this communication in error,
please re-send this communication to the sender and
delete the original message or any copy of it from your
computer system. Thank You.

Please see the official ORACLE-L FAQ:
To unsubscribe send email to:
put 'unsubscribe' in the subject line.
Archives are at
FAQ is at
Received on Thu Jul 22 2004 - 18:19:41 CDT

Original text of this message