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À
10/07/2000 13:17:21
Walter Meester
HoogkarspelPays-Bas
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Titre:
Divers
Thread ID:
00390154
Message ID:
00390351
Vues:
10
>>Bret, Josh,
>
>>I guess I have not hit any of those cases yet. All my apps seem to perform well with the DELETED index tag. My tables range from a few records to 5 million.
>
>Unless the table contains significant amounts of deleted records, you'll not get any performance benefit from a DELETED() tag.
>
>In fact, rushmore is slowing down with such low selective indexes. You may want to test performance in your cases. I would not be surpriced if you would notice significant performance gains on queries on the larger tables.
>
>About a year ago there was a discussion regarding this subject in Thread #196021 and Thread #198031. The general outcome was that only in a very few circumstances the DELETED() index tag was helpfull.
>
>- using a COUNT statement on a table with full optimization: The table is not read, the count is done by indexnodes.
>- When creating a FILTERED SQL query result. In most circumstances you want to avoid filtered sql results because they behave different from cursors.
>- When looking for DELETED records (thus looking for the minority of the table)
>- When you have large amounts of deleted records in your table.
>
>Walter,

After your post, I went out and did some searching (here and the wiki site) and found it quite interesting. I learned the deleted index from the old school. Seems the deleted index has been re-evaluated and in some cases a real issue. I will test a few things out with my app and see what happens. Thanks for your time on this.
Bret Hobbs

"We'd have been called juvenile delinquents only our neighborhood couldn't afford a sociologist." Bob Hope
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