Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Select slow
Message
De
07/09/2006 09:15:40
 
 
À
07/09/2006 03:49:25
Suhas Hegde
Dental Surgeon
Sirsi, Inde
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Titre:
Versions des environnements
Visual FoxPro:
VFP 6 SP5
Divers
Thread ID:
01149759
Message ID:
01151730
Vues:
30
>>>>
>>>>An Index caching overload effect ?
>>>>
>>>>try, and post this time:
>>>>
>>>>use bhav_data
>>>>SET EXACT ON
>>>>=lOOKUP(symbol, m.THISVALUE,symbol)
>>>>SELECT date,open,high,low,close,tottrdqty,sma9,sma12,sma26 FROM bhav_data;
>>>>where symbol = m.THISVALUE  INTO CURSOR tempDETAIL nofilter
>>>>
>>>
>>>
>>>Minimum time taken is 9 secs
>>>
>>>but if i run the second time with the same value in thisvalue it runs under .5 secs
>>>
>>>like
>>>
>>>First run with thisvalue = 'ABCD' -- 10 secs
>>>second run with thisvalue = 'dfsd' -- 10 secs
>>>third run with thisvalue = 'ABCD' -- .5 secs
>>>
>>>that is wilhout cloing the table
>>
>>this confirm the caching effect.
>>
>>try
>>
>>SELECT date,open,high,low,close,tottrdqty,sma9,sma12,sma26 FROM bhav_data;
>>where symbol = m.THISVALUE AND symbol = symbol INTO CURSOR tempDETAIL nofilter
>>
>
>No the result is the same. the above doesnt make any difference.
>Can u hilight what u mean by cashing effect ? what is going on ?

VFP load data into an internal cache ( a buffer memory).

try this ( it minimize and clear the buffer, then the execution time is more stable ?):
SYS(3050, 1, 1) minimize the buffer size

sys(1104) && unload the buffer
SELECT .... WHERE .. = m.thisvalue INTO ...
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform