Indext extent fragmentation

Hi,
On the databases I manage I notice high (50%+) extent
fragmentation when I run DBCC SHOWCONTIG against the
tables' indexes. I've run dbcc indexdefrag, dbcc
dbreindex, and create index ...with drop existing on these
indexes and they still show the same fragmentation even
after an UPDATE STATISTICS.
Is there any way to eliminate this beyond completely
dropping the indexes and starting from scratch (not a
realistic option)? The procedure I run has virtually
eliminated the logical fragmentation- are there major
performance issues with leaving them as-is?
-DanHi,
If your select statement returns all the records of a table, such table
fragmentation can cause additional page reads which will reduce the
performance of your query and utilize more resource (Memory/CPU / Disk
reads- I/O. So INDEXDEFRAG will increase the performance on fragmented
table.
One more advantage is for fragmented tables, after INDEXDEFRAG / drop and
recreate index, all the fragmented pages will be cleared and you will have
enough
free space in your database.
Thanks
Hari
US Technology
Drop and re-create a clustered index. "Dan Wunder"
<anonymous@.discussions.microsoft.com> wrote in message
news:03c101c399a6$be7b5340$a401280a@.phx.gbl...
> Hi,
> On the databases I manage I notice high (50%+) extent
> fragmentation when I run DBCC SHOWCONTIG against the
> tables' indexes. I've run dbcc indexdefrag, dbcc
> dbreindex, and create index ...with drop existing on these
> indexes and they still show the same fragmentation even
> after an UPDATE STATISTICS.
> Is there any way to eliminate this beyond completely
> dropping the indexes and starting from scratch (not a
> realistic option)? The procedure I run has virtually
> eliminated the logical fragmentation- are there major
> performance issues with leaving them as-is?
> -Dan|||Please read the whitepaper at
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/sql/maintain/optimize/ss2kidbp.asp
This explains everything you need to know.
Regards,
Paul.
--
Paul Randal
DBCC Technical Lead, Microsoft SQL Server Storage Engine
This posting is provided "AS IS" with no warranties, and confers no rights.
"Hari Prasad" <hari_prasad_k@.hotmail.com> wrote in message
news:OAqkB7dmDHA.2592@.TK2MSFTNGP10.phx.gbl...
> Hi,
> If your select statement returns all the records of a table, such table
> fragmentation can cause additional page reads which will reduce the
> performance of your query and utilize more resource (Memory/CPU / Disk
> reads- I/O. So INDEXDEFRAG will increase the performance on fragmented
> table.
> One more advantage is for fragmented tables, after INDEXDEFRAG / drop and
> recreate index, all the fragmented pages will be cleared and you will
have
> enough
> free space in your database.
> Thanks
> Hari
> US Technology
>
> Drop and re-create a clustered index. "Dan Wunder"
> <anonymous@.discussions.microsoft.com> wrote in message
> news:03c101c399a6$be7b5340$a401280a@.phx.gbl...
> > Hi,
> >
> > On the databases I manage I notice high (50%+) extent
> > fragmentation when I run DBCC SHOWCONTIG against the
> > tables' indexes. I've run dbcc indexdefrag, dbcc
> > dbreindex, and create index ...with drop existing on these
> > indexes and they still show the same fragmentation even
> > after an UPDATE STATISTICS.
> > Is there any way to eliminate this beyond completely
> > dropping the indexes and starting from scratch (not a
> > realistic option)? The procedure I run has virtually
> > eliminated the logical fragmentation- are there major
> > performance issues with leaving them as-is?
> >
> > -Dan
>