General information
Category:
Coding, syntax & commands
>>I just completed running a test using the Deleted()
>>Index tag. I created 2 Identical Tables of about
>>1.7 Million records, one with the deleted() Tag and
>>one without.
>>
>>I ran a series of identical queries and below are the results:
>>
>> With Deleted() Tag Avg of 24.4152 Seconds
>>Without Deleted() Tag Avg of 16.5155 Seconds
>>
>>And yes set deleted is ON.
>>
>>Note: SYS(3054) Returns Full optimization on "With Deleted Tag"
>> and Partial Optimization on "Without Deleted Tag".
>>
>>Go Figure!
>
>
>Patrick,
>
>According to another FoxPro programmer in the office, to fully optimize the query, the index should be:
>
> INDEX ON DELETED() FOR DELETED() TAG whatever
>
>Without the FOR clause, every record's delete status is in the deleted index, a series of .T. and .F. With the FOR clause, only the deleted records are in the index.
>
>Haven't tried this myself, but he says they tested this extensively at a previous work site.
>
>HTH
You can send that programmer to read the docs. This is from VFP on-line doc (Chapter 15):
"Rushmore can use any open indexes except for filtered and UNIQUE indexes."
A filtered index is an index that has a FOR clause.
Vlad
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