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Unexplained Select - SQL delay
Message
De
19/12/2006 19:19:40
Neil Mc Donald
Cencom Systems P/L
The Sun, Australie
 
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Problèmes
Versions des environnements
Visual FoxPro:
VFP 8 SP1
OS:
Windows XP SP2
Network:
Windows NT
Database:
Visual FoxPro
Divers
Thread ID:
01178661
Message ID:
01179090
Vues:
12
>>Try setting ANSI and EXACT ON before the select, and remove the "==" and see what happens.
>
>SET EXACT has no effect on SQL commands and "==" is the same as SET ANSI ON.

I refer you to page 130 of Tamar's Taming SQL and the example of "Smith = S" and the effect of SET EXACT OFF, with SET EXACT OFF the results may not be what you expect.

With "==" vs SET ANSI ON, it appears to make a perceivable speed difference when using "==", especially with large files.

I have come to this conclusion after extensive testing with large files, and this combined with optimizing queries with the SYS(3054,12) clause you get amazing speed results i.e. extract 8K records from a 15Mil record file with a few joins in 0.36 secs.
Regards N Mc Donald
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