optimization 
Author Message
 optimization

I used a <table> with a index (index on Nu_CDES FOR !EMPTY(NU_CDES))
If I make a SQL (SELECT * FROM <table> WHERE NU_CDES=12125), I have no
optimization (SYS(3054) says that)
I used the same <table> with a index (index on Nu_CDES ) -Without the FOR
If I make a SQL (SELECT * FROM <table> WHERE NU_CDES=12125), I have
optimization complete (SYS(3054) says that)

Is it true ? Why ?



Sat, 14 Aug 2004 17:33:33 GMT  
 optimization
This is correct, because Rushmore (VFP index optimization) cannot use
filtered indices.  The "FOR !EMPTY..." is a filter.
Quote:
> Is it true ? Why ?



Sat, 14 Aug 2004 21:36:37 GMT  
 optimization
To add to what Chaim said, the following is from the help under "Using
Rushmore to speed Data Access":

Indexing Effectively for Rushmore

Rushmore cannot take advantage of all indexes. If you use a FOR clause in
the INDEX command, Rushmore cannot use the index for optimization. For
example, because it contains a FOR clause, the following statement cannot be
optimized:

INDEX ON ORDNUM FOR DISCOUNT > 10 TAG ORDDISC

Similarly, Rushmore cannot use an index created with a NOT condition. For
example, the following expression can be optimized:

INDEX ON DELETED() TAG DEL

But this one cannot:

INDEX ON NOT DELETED() TAG NOTDEL

--
David Dunetz
SweetWARE


Quote:
> This is correct, because Rushmore (VFP index optimization) cannot use
> filtered indices.  The "FOR !EMPTY..." is a filter.

> > Is it true ? Why ?



Sun, 15 Aug 2004 01:18:04 GMT  
 
 [ 3 post ] 

 Relevant Pages 

1. Optimization question

2. Optimization

3. FoxPro 2.6 for DOS, code optimization

4. Rushmore optimization ?

5. JOIN Optimization

6. Query Optimization

7. Help with optimization

8. VFP Rushmore optimization not kicking in

9. Search optimization

10. SQL statement optimization

11. Cutting Length Optimization

12. Query Optimization

 

 
Powered by phpBB® Forum Software