>>>>>>>>>
>>>>>>>>>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)
>>>>>SELECT .... WHERE .. = m.thisvalue INTO ...
>>>>>
>>>>
>>>>
>>>>No help
>>>>same effect
>>>
>>>
>>>>I put the SYS(3050, 1, 1) in init of the form or should i put it before the query ?
>>>
>>>One time is sufficient
>>>>sys(1104)
>>>>SELECT .... WHERE .. = m.thisvalue INTO
>>>
>>>Rerun VFP, and post the output of this:
>>>
>>>for k=1 to 5
>>> sys(1104)
>>> t1=seconds()
>>> SELECT .... WHERE .. = m.thisvalue INTO
>>> ? seconds()-m.t1
>>>next
>>>
>>
>>
>>returned
>>
>>9.838
>>0.0339
>>0.0149
>>0.0149
>>0.017
>
>
>9.838 - VFP reads data from hard drive into RAM.
>
>.0339 - VFP uses data in RAM - CACHE - not read from hard drive.
what should i do to speed it up?
