Re: ghosted and forwarded records ?

From: Greg Linwood (g_linwoodQhotmail.com)
Date: 07/25/04 

Date: Sun, 25 Jul 2004 14:18:37 +1000

Definitely, as the physical storage location of the rows is dispersed.

Regards,
Greg Linwood
SQL Server MVP

"Hassan" <fatima_ja@hotmail.com> wrote in message
news:%23mL0lqHcEHA.3716@TK2MSFTNGP11.phx.gbl...
> Does this cause some kind of logical fragmentation then ?
>
> "Greg Linwood" <g_linwoodQhotmail.com> wrote in message
> news:%23t8bwY8bEHA.2476@TK2MSFTNGP09.phx.gbl...
> > Hi Hassan
> >
> > Ghosted records are records marked for lazy deletion by a system
process.
> >
> > Forwarded records only occur on tables without clustered indexes -
> "Heaps".
> > In the case where a row is updated so that it is wider & no longer fits
on
> a
> > page, it is "forwarded" to another page & a forwarding marker left in
its
> > original place. This helps avoid updating Non-Clustered Indexes (NCI)
> which
> > might be on the heap because NCIs on Heaps use File Page Row (FPR)
> pointers
> > on the leaf nodes. If forwarding records weren't used, indexe FPRs would
> > also need to be updated immediately upon such row updates when the row
no
> > longer fits on the page it was on.
> >
> > So, forwarding rows avoid needing to update FPRs on NCI leaf nodes when
> rows
> > are updated so they no longer fit on a page.
> >
> > HTH
> >
> > Regards,
> > Greg Linwood
> > SQL Server MVP
> >
> > "Hassan" <fatima_ja@hotmail.com> wrote in message
> > news:%23SeSGl7bEHA.3580@TK2MSFTNGP11.phx.gbl...
> > > What are ghosted and forwarded records ?
> > >
> > >
> >
> >
>
>

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