Here's the reply
When ON the worktable creation for correlated subquery reformatting will not be placed as early as as possible.
Con : The worktable may be truncated and filled multiple times.
Pro : May help with some obscure cases when worktable creation may be placed incorrectly breaking dependency on other worktables
Specically :
- if the StoreInd from subquery depends on other worktables it is placed on the top of the subquery
- other reformat worktables (not from correlated subqueries) are placed as before, that is on the top of the current Sequencer operator
Hope this helps.