There is a limit on the number of tables considered while building the qep
(max 32 I think). Are there so many tables in your query so that this limit
is being reached ?

-----Original Message-----
From: Mark Costello [mailto:costello@dmt.com]
Sent: Friday, May 27, 2005 5:49 PM
To: info-ingres@cariboulake.com
Subject: [Info-ingres] Index not considered

Hi All,

I have a query that once used a secondary index that no longer uses the
index. I've reviewed all plans using the op255 <plan#> flag and a plan
isn't even being considered using the index. I understand that it may not
consider using the index to be the best alternative but shouldn't it always
consider it as an option? The "no timeout" is shown in the QEP so it isn't
giving up. I've verified, using statdump, that the base table optimization

stats for the index column was generated after the index was created.

Also, I have a nearly identical development system that generates additional

QEP options that use the index.

The question is, what can cause an index to be ignored when the optimizer is

generating plan alternatives?

Thanks,

Mark Costello
DMT, Inc.


_______________________________________________
Info-ingres mailing list
Info-ingres@cariboulake.com
http://mailman.cariboulake.com/mailm...py/info-ingres

There are only 3 tables in the query and two of the tables have a single
index.

Thanks,
Mark


<Piotr.Wisniewski@breat.com.pl> wrote in message
news:mailman.1117625221.13372.info-ingres@cariboulake.com...
> There is a limit on the number of tables considered while building the qep
> (max 32 I think). Are there so many tables in your query so that this
limit
> is being reached ?
>
> -----Original Message-----
> From: Mark Costello [mailto:costello@dmt.com]
> Sent: Friday, May 27, 2005 5:49 PM
> To: info-ingres@cariboulake.com
> Subject: [Info-ingres] Index not considered
>
> Hi All,
>
> I have a query that once used a secondary index that no longer uses the
> index. I've reviewed all plans using the op255 <plan#> flag and a plan
> isn't even being considered using the index. I understand that it may not
> consider using the index to be the best alternative but shouldn't it
always
> consider it as an option? The "no timeout" is shown in the QEP so it
isn't
> giving up. I've verified, using statdump, that the base table
optimization
>
> stats for the index column was generated after the index was created.
>
> Also, I have a nearly identical development system that generates
additional
>
> QEP options that use the index.
>
> The question is, what can cause an index to be ignored when the optimizer
is
>
> generating plan alternatives?
>
> Thanks,
>
> Mark Costello
> DMT, Inc.
>
>
> _______________________________________________
> Info-ingres mailing list
> Info-ingres@cariboulake.com
> http://mailman.cariboulake.com/mailm...py/info-ingres