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Help Optimizing a query
Message
De
14/08/2001 14:55:31
 
 
À
14/08/2001 14:22:48
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00542086
Message ID:
00543684
Vues:
16
>>>>>1. I am accessing the data locally.
>>>>>2. The total number of records is 7,127.
>>>>>3. The speed is approximately 17 seconds with this data set.
>>>>>
>>>>
>>>>Did you tried to delete tags all and add them one by one by adding a new condition? 17 sec. seems too long for me. It should be 1-3 sec. Did you try it on different machines?
>>>>
>>>>>>Did you access this table locally or through the network? What's the number of records in a table and what speed do you get?
>>>>>>
>>>
>>><snip>
>>>
>>>The last thing I tried was to create a simple index which would return 20000 records. This test CDX contains no other indexes other that the one index. I ran a test on this one index and it still took 27+ seconds on my machine.
>>
>>Can you please provide more details? Especially, what is the SQL - SELECT command, and what index(es) you have?
>>
>>Hilmar.
>
>In this case I have a table with about 1.2 million records.
>I have a character field which as a width of one called RampCode.
>I have one index only on the RampCode field.
>As a pre-digest idea, I was going to store the values into this table so that
>my Sql would be basically like this.
>
>Select * From VinData Where RampCode = lcRampCode Into Cursor qDetails NoFilter
>
>This takes approximately 21 seconds. I've updated the time from 27+. That was with SET DELETED ON.

First, I wonder why the time changed at all once DELETED was set OFF?
You call it a "test CDX". Does that mean that this is a separate CDX, apart from the 'production' CDX?
If VINDATA records are wide, then naming the desired fields should make a significant difference.

Honestly, I've found this thread a bit hard to follow. It seems that you report latest result without reporting how the query/data/indexes differed. It might help to have all of the facts.

good luck
JimN
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