12.5.0.3
Is there any reason why update statistics works ok but update index
statistics runs out of space on tempdb? I'm migrating and am trying to work
out what works for a very large table.

Martin

"Movilla Martin" <postmaster@SPAMIGNOREmovilla.IGNOREplus.com> wrote
in message news:17MIb.7461$tQ6.77982@wards.force9.net...
> 12.5.0.3
> Is there any reason why update statistics works ok but update index
> statistics runs out of space on tempdb? I'm migrating and am trying
to work
> out what works for a very large table.
>
> Martin
>


This can happen: unlike 'update statistics', 'update index
statistics' needs to perform a sort operation: the latter needs to
sort the values of the non-leading index columns in order to make a
histogram, while the former only looks at the leading index column,
which by definition is already sorted in the index.
This sorting requires space in tempdb for a worktable, and for a
sufficiently large table you may not have enough of that.

Suggestion: try to use the new 'sampling' option for 'update
statistics' on large tables. This hould reduce your tempdb space
requirement as well as speed up the entire process.

HTH,

Rob
-------------------------------------------------------------
Rob Verschoor

Certified Sybase Professional DBA for ASE 12.5/12.0/11.5/11.0
and Replication Server 12.5

Author of "Tips, Tricks & Recipes for Sybase ASE" and
"The Complete Sybase ASE Quick Reference Guide"
Online orders accepted at http://www.sypron.nl/shop

mailto:rob@YOUR.SPAM.sypron.nl.NOT.FOR.ME
http://www.sypron.nl
Sypron B.V., P.O.Box 10695, 2501HR Den Haag, The Netherlands
-------------------------------------------------------------

"Rob Verschoor" <rob@DO.NOT.SPAM.sypron.nl.REMOVE.THIS.DECOY> wrote in
message news:3ff54a4f$0$175$1b62eedf@news.wanadoo.nl...
> "Movilla Martin" <postmaster@SPAMIGNOREmovilla.IGNOREplus.com> wrote
> in message news:17MIb.7461$tQ6.77982@wards.force9.net...
> > 12.5.0.3
> > Is there any reason why update statistics works ok but update index
> > statistics runs out of space on tempdb? I'm migrating and am trying
> to work
> > out what works for a very large table.
> >
> Suggestion: try to use the new 'sampling' option for 'update
> statistics' on large tables. This hould reduce your tempdb space
> requirement as well as speed up the entire process.

Thanks Rob. I'm reading up on the white paper now.

Martin