RE: When to rebuild the index?

  • From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
  • To: <chiragdba@xxxxxxxxx>
  • Date: Tue, 6 Sep 2005 09:27:16 -0700

No, a select cannot cause an index split, and index splits do not necessarily 
warrant rebuilding anyway.  Check out the following paper for an excellent of 
discussion of when (very rarely) and why to rebuild indexes, or do a search on 
asktom.oracle.com:
 
www.actoug.org.au/Downloads/ 
<http://www.actoug.org.au/Downloads/oracle_index_internals.pdf> 
oracle_index_internals.pdf
 
You have to run ANALYZE INDEX index_name VALIDATE STRUCTURE; to populate the 
index_stats view - and beware that this analyze will require a lock so you may 
want to run it after hours.
 
Regards,
Brandon
 
 

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On 
Behalf Of Chirag DBA
Sent: Tuesday, September 06, 2005 9:04 AM
To: Chirag DBA
Cc: Oracle-L Freelists
Subject: When to rebuild the index?


Hi Guys,
 
I think that even select statement will make the index split and require the 
rebuilding. Am I true? I think I am.
 
And there is a view called index_stats with column height. 
 
I have read that when the value of this column is >= 4, u need to rebuild the 
indexes.
But after analyzing the particular schema, I don see any value to get populated 
in this view.
 
I can see last analyzed value changed in dba_indexes when I analyze the schema 
with DBMS_STATS. ANALYZE_SCHEMA package.
 
Why this is so? 
 
Regards - Chirag 
 


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