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Message Posted: Fri, 07 Oct 2005 @ 15:11:42 GMT

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Rachana,

Pros:

1) Your queries can run much faster.

2) System maintains the Summary tables. They won't get out of sync.

Some good places to use:

1) great place to use it: Alternate Primary index

2) Another great place to use it is on most often used date range however PPI might work better. Example of this is a versioned table where you only normally want the current copy.

3) Aggregations that are done many times a day.

4) Any repetitive query or portion of a query that is done many times a day.

Cons (most of:

1) System maintains the tables automatically. You cannot control the timing of the updates.

2) Inserts to the base table even if they don't add data will cause the Join Index to be maintained. This can eat a lot of CPU and IO if it is done quite often. (

3) MORE DASD requirements.

Thanks,

Bob Diehl

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