a good article on the new derived key indexes in v6r1 in IBM database
esp interesting reading at the end of the article. There is a new RCDFMT
clause in the CREATE INDEX statement which allows the created index to be
seen as a logical file for record level i/o.
CREATE INDEX STARTEST.BIGREVENUE ON STARTEST.ITEM_FACT (SUPPKEY ASC,
QUANTITY * EXTENDEDPRICE ASC)
WHERE QUANTITY * EXTENDEDPRICE > 100000
RCDFMT BSUPPREV ADD QUANTITY, EXTENDEDPRICE, REVENUE_WO_TAX, REVENUE_W_TAX;
"...Before V6R1, the existence of DDS-created Select/Omit logical files
would force queries against the underlying table or associated physical file
to be routed to the old Classic Query Optimizer (CQE). You can override that
behavior using the IGNORE_DERIVED_INDEX *YES QAQQINI file option. With V6R1,
queries using the underlying table or physical file from those DDS
Select/Omit logical files, will be routed to the new SQE unless you have
explicitly specified IGNORE_DERIVED_INDEX *NO in your QAQQINI file. The SQE
optimizer will not use DDS Select/Omit logical file indexes. ..."