Re: EVI recommendation

Let's talk about these distinct values. Suppose you have an item master
with over a million different items in it. Now let's suppose there are
only about a dozen item classes and each item belongs to one of these
twelve classes. The index advisor will probably recommend you build an
EVI over item class in the item master. This is what they mean by 'a few
distinct values'. I would find it rather odd that the index advisor would
advice you to create an EVI over some column(s), let's call it PrimaryKey,
which never repeats in the 1.3 million rows you have in this table.

Let's say your table has two columns: SequenceNumberUsed and
SequenceType. You have a hundred or so values for SequenceType like
CustomerOrderNumber, PurchaseOrderNumber, ShopOrderNumber and so on. And
SequenceNumberUsed may be a large variety of numbers you used for each of
these. So you have thousands of rows for the type CustomerOrderNumber and
so on. Again, the advisor might recommend you create an EVI over
SequenceType.

I'm really trying to understand your layout more.

Now, if you're insisting you be able to CHAIN with RPG instead of SELECT
with SQL the question becomes do you:
- try to use chain on the EVI and see if that works
- If not, abandon the EVI and create a logical or binary index instead
- If not, create both the EVI and a binary index
- forego insistening
- Just create a binary index and ignore the recommendation, if it
reappears.


Rob Berendt