>I'm thinking, could it be better to use filtered index instead.
>
>E.g. currently I do:

>scan for m.plError=.f. and SearchTB = m.lcSearch and not empty(InsCommand)

>
>May be it would be faster to set a filtered index and do seek, when scan while?
>
>However, as I recall, I tried similar idea (in another context, though) and it actually slowed it down.
>
>>

INDEX ON EMPTY (MyField) TAG E_MyField
>>SET FILTER TO NOT EMPTY (MyField)

HTH
>>
>>>If I want to filter all non-empty values for character (100) field, what would be the best expression for the index (if I need the index)?

* define this index
INDEX ON SearchTB TAG TAGOPTIM FOR NOT empty(InsCommand) && AND NOT DELETED() 

On Routine

SET ORDER TO TAGOPTIM
SEEK m.lcSearch
scan WHILE SearchTB = m.lcSearch AND !m.plError
...
ENDSCAN