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Posted by Erland Sommarskog on 10/14/05 00:22
kmounkhaty@yahoo.com (smounkhaty@bremer.com) writes:
> I've been new company for only a month and started analysing Index
> Fragmentation.
>
> After I ran DBCC DBREINDEX and capture data into permanent table, I 've
> seen lots of tables with no indexes. These tables showed:
>
> Very low scan density,
> High extent fragmentation
> High Avg. Bytes Free per Page
>
> What are the best strategies to defragment tables with no indexes?
Create a clustered index on them. If the index is absolute undesired,
drop the index once your done.
> I'm planning to make a rule that each table must have a clustered index
> and this index must be created on the best column (highest
> selectivity).
Yes, that is a good rule. Heap tables with deletions can easily become
very fragmented.
As for which column to cluster on, you may want to find a column
that grows monotonically, if all you want to do is avoid fragmentation.
Of course, adding indexes to improve queries is a good idea too!
--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
Books Online for SQL Server SP3 at
http://www.microsoft.com/sql/techinfo/productdoc/2000/books.asp
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