Re: Filtered Indexes

[Charles Wilt <charles.wilt@xxxxxxxxx>]

Just because you think it'd be helpful to use the index, doesn't mean
it actually would....or that the system agrees :)

If the performance is acceptable, don't worry about it....trust the system.

Otherwise...what does Visual Explain say?

Some possible reasons, that could be explored via VE:
- #rows selected vs. the number of rows in the table
- ORDER BY on the statement
- function usage


Charles


On Mon, Mar 28, 2011 at 3:38 PM, Ryan Hunt <ryan.hunt@xxxxxxxxxxxxx> wrote:
> Can't get DB/400 to use a filtered index (binary radix index with a where
> clause).  I even created one as a test that was ridiculous and met up a
> exactly with the where clause of a query and should have been able to use
> index only access.  Yet, I can't get our system to use it.
>
> We're on V6R1.  Is there some requirement I might be missing?  For example,
> I know that index/table partitioning only works if DB2 Multisystem is
> installed.  Is there some similar requirement for using indexes creating
> with a WHERE clause??
>
> Thanks
>
> Ryan
>
>
>
> --
> This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list
> To post a message email: MIDRANGE-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/midrange-l
> or email: MIDRANGE-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/midrange-l.