Extents

I am running a series of consistancy checks against our
SQL Server 6.5 databases to ensure the integrity of the
data prior to migration to 2000. I am noticing that
several of our databases have thousands of extents. Does
SQL Server complely manage how it allocates its primary
data allocation as well as the extents? In other words,
does the administrator have any control as to how table
space is allocated? Doesn't performance decrease as the
number of extents is generated? Should I be concerned
with the thousands of extents I am seeing. Thanks.I wouldn't be too concerned unless for some reason the scan densities are
way too low,
such as extreme data modification over time resulting in lots of data
movement.
Run DBCC SHOWCONTIG on your largest tables to see what's up with that.
Otherwise, just let the server run its own show. It knows which extents are
allocated and which aren't, and does this on its own.
James Hokes
"NewGuy" <anonymous@.discussions.microsoft.com> wrote in message
news:00c301c3c8c2$f84f40e0$a501280a@.phx.gbl...
> I am running a series of consistancy checks against our
> SQL Server 6.5 databases to ensure the integrity of the
> data prior to migration to 2000. I am noticing that
> several of our databases have thousands of extents. Does
> SQL Server complely manage how it allocates its primary
> data allocation as well as the extents? In other words,
> does the administrator have any control as to how table
> space is allocated? Doesn't performance decrease as the
> number of extents is generated? Should I be concerned
> with the thousands of extents I am seeing. Thanks.|||The more data the more extents you will have. Your fill factor can have a
large influence on that as well as any fragmentation. When it gets migrated
to sql server it will get rearranged anyway so I wouldn't be too concerned
until after you convert it all. Just make sure there aren't any errors
shown by the CHECKDB or any of the associated DBCC commands before you move
it.
--
Andrew J. Kelly
SQL Server MVP
"NewGuy" <anonymous@.discussions.microsoft.com> wrote in message
news:00c301c3c8c2$f84f40e0$a501280a@.phx.gbl...
> I am running a series of consistancy checks against our
> SQL Server 6.5 databases to ensure the integrity of the
> data prior to migration to 2000. I am noticing that
> several of our databases have thousands of extents. Does
> SQL Server complely manage how it allocates its primary
> data allocation as well as the extents? In other words,
> does the administrator have any control as to how table
> space is allocated? Doesn't performance decrease as the
> number of extents is generated? Should I be concerned
> with the thousands of extents I am seeing. Thanks.|||Andrew,
LOL. I guess I could have read 'prior to migration'.
Silly me. :-)
James Hokes
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:#szC0ENyDHA.3196@.TK2MSFTNGP11.phx.gbl...
> The more data the more extents you will have. Your fill factor can have a
> large influence on that as well as any fragmentation. When it gets
migrated
> to sql server it will get rearranged anyway so I wouldn't be too concerned
> until after you convert it all. Just make sure there aren't any errors
> shown by the CHECKDB or any of the associated DBCC commands before you
move
> it.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "NewGuy" <anonymous@.discussions.microsoft.com> wrote in message
> news:00c301c3c8c2$f84f40e0$a501280a@.phx.gbl...
> > I am running a series of consistancy checks against our
> > SQL Server 6.5 databases to ensure the integrity of the
> > data prior to migration to 2000. I am noticing that
> > several of our databases have thousands of extents. Does
> > SQL Server complely manage how it allocates its primary
> > data allocation as well as the extents? In other words,
> > does the administrator have any control as to how table
> > space is allocated? Doesn't performance decrease as the
> > number of extents is generated? Should I be concerned
> > with the thousands of extents I am seeing. Thanks.
>