I am converting VFP7 application to VFP9 (SP1, version 3504).
There is a table with ~5 million records having regular index expression based on four character fields: updflag+station+rec_type+grade

I need to collect ~300 records using expression like:

SELECT * from porthist where updflag+station+rec_type+grade=” “

If enginebehavior is 70, it takes less than 0.5 sec, but if enginebehavior is 90, it takes more than 15 sec!

SYS(3054,1) displays Rushmore optimization level NONE for 90, and PARTIAL for 70.
Set optimize is ON
Set ANSI is OFF
Table has been packed and reindexed.

What is wrong / What could be done with “select” here?

(Sure, instead of select I can set order on the table, and copy 300 records to the temporary table, but I would like to understand what can be done here with select).

Thanks in advance.