On Wed, 9 Apr 2003 10:26:14 -0500
William Goliak <wgoliak AT MIDWAY.UCHICAGO DOT EDU> wrote:

> Make sure you audit your database first.  Any db errors will cause the
> reload to fail.
>

on the notion of unloaddb/loaddb:

IMHO, if this has any effect on db performance, this effect is not
longlasting, it cannot be, therefore, _if_ you really have performance
problem on the db, find the current bottleneck in hardware (cpu/memory/disk)
and fix that.

on audit db:

don't do that unless IBM support tell you to do so, and even then, be very
carefull, a 60 GB db takes between 1 and 20 (or more) days to audit,
depending on the hardware... We did an auditdb of our 75 GB DB (actual
occupied space) and it only took about 100-something hours... btw, that
didn't fix the problem, so we were very glad we didn't take production down
for 4.5 days... ;-)

>
> >
> > Another of my problems is that expiration hasn't been able to run from
> > beginning to end, I set a duration of approximately 7 hours.  Could this
> > also be causing performance/DB growth?  Thanks!
> >
> > Available Space (MB): 60,456
> >         Assigned Capacity (MB): 60,456
> >         Maximum Extension (MB): 0
> >         Maximum Reduction (MB): 8,044
> >              Page Size (bytes): 4,096
> >             Total Usable Pages: 15,476,736
> >                     Used Pages: 12,913,875
> >                       Pct Util: 83.4
> >                  Max. Pct Util: 83.5
> >               Physical Volumes: 26
> >              Buffer Pool Pages: 24,576
> >          Total Buffer Requests: 4,229,185
> >                 Cache Hit Pct.: 98.30
> >                Cache Wait Pct.: 0.00
> >            Backup in Progress?: No
> >     Type of Backup In Progress:
> >   Incrementals Since Last Full: 9
> > Changed Since Last Backup (MB): 149.34
> >             Percentage Changed: 0.30
> > Last Complete Backup Date/Time: 04/09/2003 09:32:43
> >
> >


0.3 % changes since the last (incremental) backup, our db does a lot less in
about 11 hours, and our db is a bit bigger than yours. It does make me
wonder, what is going on? Do you by accident have a lot of the dbvols
sitting on the same disk? physical vols says 26, s I guess you're using
files, not raw volumes... having a lot of small db files scatterd over one
disk will impact db performance badly...


--
Met vriendelijke groeten,

Remco Post

SARA - Stichting Academisch Rekencentrum Amsterdam    http://www.sara.nl
High Performance Computing  Tel. +31 20 592 8008    Fax. +31 20 668 3167

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