Re: Optimizer using the wrong index

"Martin" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>...
> Hiyas,
> 
> We use ASE 11.5.1 on AIX 4.3. We've recently hit a problem (just started a
> month ago) with the wrong index being used on a production server greatly
> slowing down selects/updates. The strange thing is, copies of the database
> to test servers dont have this problem. Selects on the test server use a
> faster nonclustered index while the production server uses the clustered
> index which is much slower in the selects. We've had little luck with sybase
> support so far on this issue. Data distribution seems to be the only phrase
> uttered to us. Fragmentation is also a favourite. No meaningful answers on
> how we can check this or resolve it. Any ideas?
> 
> Martin

The usual starting point for analyzing this kind of performance and
tuning issue is to look at the output of "set showplan on" as well as
traceflag 302 and 310 output.  I recommend reading the 12.5.1 P&T
Guide, chapter 7 for an explanation of such output. 
http://sybooks.sybase.com:80/onlinebooks/group-as/asg1251e

While there have been a number of changes in the optimizer since
11.5.x, the basic information given by these commands is still the
same (I believe there have been formatting changes, though).  If that
doesn't help you make sense of the output, post it here and you may
get some good commentary on it.

Cheers,

-bret