We have a bad query plan on a query which I can't see why its been chosen.
Its doing table reformatting which we can solve with a set store_index off.
The indexes have been reorg-ed and the stats are up-to-date.
I tried set option show_lio_costing on and looked at the output but it was rather large to understand.
( I also tried set option show_lio_costing on on a 2 table join and the output was over 400 lines long)
Is there a guide to understanding the output of these options ?
What's the most important lines I should be looking for ?
A very useful feature for the the next version of ASE would be a mechanism to present a simple explanation of the query plan selection.