DBCC INDEXDEFRAG - Interleaved on the disks

DBCC INDEXDEFRAG will not help if two indexes are
interleaved on the disk.
I see this everyone, but what does "interleaved on the
disk" mean? Is that a composite index?
Please send replies to: mikecathey@.hotmail.comThis means that the index pages are not contiguous on the disk. The defrag
operation sorts the contents of the index pages (logical order) without
rearranging the physical order of the pages on the disk.
You have to rebuild the indexes to rearrange the physical layout of the
pages on disk.
"Mike Cathey" <mikecathey@.hotmail.com> wrote in message
news:c95f01c38219$55c20dc0$a601280a@.phx.gbl...
> DBCC INDEXDEFRAG will not help if two indexes are
> interleaved on the disk.
> I see this everyone, but what does "interleaved on the
> disk" mean? Is that a composite index?
> Please send replies to: mikecathey@.hotmail.com
>|||DBCC INDEXDEFRAG defragments the leaf level of an index so that the physical
order of the pages matches the left-to-right logical order of the leaf
nodes. However, the key here is that, it does this "in-place". So, if you
have two indexes that are interleaved on the disk, and let us say that all
the physical order of the pages match left-to-right logical order, then
indexdefrag will not be able to improve performance.
If you are planning to improve performance and your problem is
interleaved indexes, you want to improve the clustering of the pages - for
which indexdefrag is not the right tool - rebuilding the indexes is the what
you should do. If fragmentation is your problem, then you should use
indexdefrag.
HTH,
Shriram
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"Don Peterson" <no1@.nunya.com> wrote in message
news:eESYGKigDHA.3128@.tk2msftngp13.phx.gbl...
> This means that the index pages are not contiguous on the disk. The
defrag
> operation sorts the contents of the index pages (logical order) without
> rearranging the physical order of the pages on the disk.
> You have to rebuild the indexes to rearrange the physical layout of the
> pages on disk.
> "Mike Cathey" <mikecathey@.hotmail.com> wrote in message
> news:c95f01c38219$55c20dc0$a601280a@.phx.gbl...
> > DBCC INDEXDEFRAG will not help if two indexes are
> > interleaved on the disk.
> >
> > I see this everyone, but what does "interleaved on the
> > disk" mean? Is that a composite index?
> >
> > Please send replies to: mikecathey@.hotmail.com
> >
> >
>