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ARGHH! big table killing VFP - need strategy help!
Message
De
06/08/1999 15:32:49
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Divers
Thread ID:
00250826
Message ID:
00250865
Vues:
19
Already have the fields indexed

no deleted records and Set deleted is off

thanks anyway!
Ken

>Hi,
>
>I would create more indexes to speed up the process:
>
>1. on Deleted()
>2. on pnumber
>3. on gamedate
>
>HTH
>
>>Hi,
>>
>>I've ot a 15.6 million row table (play.dbf) - (only 16 small columns) - that I need to do some data analysis on. Problem is that some aggregate functions drive VFP to an absolute standstill - not just slow - but down to nothing! I need help with a strategy to deal with this.
>>
>>Example: two of the columns are pnumber (patron number) and gamedate. Every patron can have multiple records for each gamedate.
>>
>>First, I wanted a count of how many records per day existed (this goes over a little less than 2 years) so I ran:
>>
>>"select gamedate, count(gamedate) from play group by gamedate" -
>>
>>It was slow compared to what I'm used to, but ran fine and gave me proper results. There were about 600 separate days where play happened - so thus about 600 rows returned. NOW - I want a result with the unique patrons in it - in other words - I wanna see all the different pnumbers in the table? So I try both:
>>
>>select distinct pnumber from play ..... and .... select pnumber from play group by 1
>>
>>both drive VFP to a halt! - Waited fifteen minutes and barely go to 1% on the query thermometer! tried it several times and had to force quit each time. As a note, I would expect a result set of about 100,000 rows in this case.
>>
>>An attempt to do aggregate like "Select pnumber, gamedate, count(*) from play group by 1, 2" never even made it to 1% after fifteen minutes! ARGGHHHH! I've got a lot of these kind of aggregates to do as well as cross tabs and there is no way I can wait twenty or thirty minutes on each one.
>>
>>Any advice on strategy would be greatly appreciated. (BTW - this is on VFP 6 SP3, Dell PII-450 128kRAM - both fields mentioned above are indexed.)
>>
>>TIA!
Ken B. Matson
GCom2 Solutions
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