Hi,





I have a query which is run across 3 tables JOB_TYPE_FIRST,
JOB_TYPE_SECOND and JOB_ALLOCATION_WORKLIST.



The column JOBID is referenced in JOB_ALLOCATION_WORKLIST table and
primary key in both JOB_TYPE_FIRST, JOB_TYPE_SECOND tables.



There is one more column BOOK_ID which is supplied as the binding
parameter to the query. The query looks like:



select count(distinct(j.JOBID)) as jobCount

from JOB_TYPE_FIRST a, JOB_TYPE_SECOND b, JOB_ALLOCATION_WORKLIST j

where (( a.JOBID = j.JOBID)

and (a.BOOK_ID = :bookId))

or ((b.JOBID = j.JOBID)

and (b.BOOK_ID = :bookId));



As the records in the database are too large it is having huge cost and
stalling the server and takes lot of time.



Can anyone suggest a better way to fetch the results for the query or
tune it? Any help would be highly appreciated.





Thanks & Regards,

Kapil


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Hi kapil,

Here you have specified 3 tables, does JOB_TYPE_FIRST and JOB_TYPE_SECOND
both contain all the JOBID in the third table?

Maybe i can help you if you elaborate your problem a bit more.

Regards,
Moiz Kothari

On Thu, May 15, 2008 at 11:30 AM, <kapil.munish@wipro.com> wrote:

> Hi,
>
>
>
>
>
> I have a query which is run across 3 tables JOB_TYPE_FIRST, JOB_TYPE_SECOND
> and JOB_ALLOCATION_WORKLIST.
>
>
>
> The column JOBID is referenced in JOB_ALLOCATION_WORKLIST table and primary
> key in both JOB_TYPE_FIRST, JOB_TYPE_SECOND tables.
>
>
>
> There is one more column BOOK_ID which is supplied as the binding parameter
> to the query. The query looks like:
>
>
>
> select count(distinct(j.JOBID)) as jobCount
>
> from JOB_TYPE_FIRST a, JOB_TYPE_SECOND b, JOB_ALLOCATION_WORKLIST j
>
> where (( a.JOBID = j.JOBID)
>
> and (a.BOOK_ID = :bookId))
>
> or ((b.JOBID = j.JOBID)
>
> and (b.BOOK_ID = :bookId));
>
>
>
> As the records in the database are too large it is having huge cost and
> stalling the server and takes lot of time.
>
>
>
> Can anyone suggest a better way to fetch the results for the query or tune
> it? Any help would be highly appreciated.
>
>
>
>
>
> Thanks & Regards,
>
> Kapil
>
> * Please do not print this email unless it is absolutely necessary. *
>
> The information contained in this electronic message and any attachments to
> this message are intended for the exclusive use of the addressee(s) and may
> contain proprietary, confidential or privileged information. If you are not
> the intended recipient, you should not disseminate, distribute or copy this
> e-mail. Please notify the sender immediately and destroy all copies of this
> message and any attachments.
>
> WARNING: Computer viruses can be transmitted via email. The recipient
> should check this email and any attachments for the presence of viruses. The
> company accepts no liability for any damage caused by any virus transmitted
> by this email.
>
> www.wipro.com
>



--
Hobby Site : http://dailyhealthtips.blogspot.com

On Fri, 2008-05-16 at 09:21 -0600, Scott Marlowe wrote:
> On Thu, May 15, 2008 at 12:00 AM, <kapil.munish@wipro.com> wrote:
> > Hi,
> >
> > select count(distinct(j.JOBID)) as jobCount
> > from JOB_TYPE_FIRST a, JOB_TYPE_SECOND b, JOB_ALLOCATION_WORKLIST j
> > where (( a.JOBID = j.JOBID)
> > and (a.BOOK_ID = :bookId))
> > or ((b.JOBID = j.JOBID)
> > and (b.BOOK_ID = :bookId));
>
> Have you tried joining a with j and b with j separately, and then
> doing a union on those two sets?

That seems the only way to get a sane answer to this query, which is
otherwise an unconstrained join on both sides of the OR. Great example
of a query which runs slow because the question is phrased incorrectly.
Count(distinct) is pretty much the only function that will give the same
answer as a correctly phrased query.

--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support


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