dispute on index usage with union view

[blom0344]

Last week I had an interesting dispute with a developer who insisted that the use of a union view would effectively cause the optimizer to skip the use of indices in an execution plan. I no longer have a DB2 instance to test on, so I tried something similar in Oracle 9i.
I cannot really reproduce this. As long as I use conditions that relate to a table column that is indexed execution plans seem to be okay.
Anyone comments?

Ties Blom

 

[ddiamond]

I can confirm that that is not a problem for oracle 9i.

 

[MarcLodge]

Could you get the developer to Explain a simple query that accesses the union view on a full index key?

Marc