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database fragmentation [message #461104] Wed, 16 June 2010 10:07 Go to next message
Nau
Messages: 24
Registered: October 2004
Junior Member

I have a question about database fragmentation.

I know that fragmentation can reduce performance in query times. The blocks are distributes in many extents and scans process takes a long time. Oracle engine have to locate the address
of the next extent..

I want to know if there is any system view in which you can check if your table or index has high fragmentation. If it's needed I will have to re-create, move or rebulid the table or index, but before I want to know if the degree of fragmentation is high.

Any useful script or query to do this, any interesting oracle system view??

Any advice will bre greatly apreciatted.

Thanks in advance
Re: database fragmentation [message #461106 is a reply to message #461104] Wed, 16 June 2010 10:11 Go to previous messageGo to next message
Michel Cadot
Messages: 68650
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
dba_extents
Then you have to define your criteria for "fragmentation".

Regards
Michel

[Updated on: Thu, 17 June 2010 12:51]

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Re: database fragmentation [message #461395 is a reply to message #461106] Thu, 17 June 2010 12:42 Go to previous message
Kevin Meade
Messages: 2103
Registered: December 1999
Location: Connecticut USA
Senior Member
AS oracle improves, fragmentation has become less and less a topic of interest. You can do a google to find a lot of talk about it, but you may also note that most of these are older web pages, pdf, and doc files etc.

If you are using locally managed tablespaces then most issues with fragmentation have gone away.

Still, if you need some kind of report, I am sure OEM can provide one (though I know not where to look for it), and you can try some of the scripts to be found online.

Good luck, Kevin

[Updated on: Thu, 17 June 2010 12:42]

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