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21/05/2003 10:45:29
Walter Meester
HoogkarspelPays-Bas
 
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Problèmes
Titre:
Divers
Thread ID:
00790246
Message ID:
00791071
Vues:
28
Hi robin,

>If you open your database with deleted on, if there are lots of deleted records at the beginning of the table, this will cause a delay as Foxpro will search to the first undeleted record.
>
>You can speed this by setting up a CDX on deleted(), then Foxpro will use the index to go quickly to the first record. There has been different views on if this really speeds things up or not in different situations, anyway, if there's at least 10% of deleted records i'd say its best to do it.

This is really a bad advice. The INDEX ON DELETED() should never be used except for very specific cases. If you index a million record table this way, and try to open this table through a slow network, it might take ages to open the table since rushmore has to load about the whole indextag to find the first non deleted record in the table. This is one of the most nasty pitfalls of the INDEX ON DETELED() tag.

It is way better to avoid situation where large numbers of deleted records occur at the beginning of the table, by either reusing records of by packing the table periodically.

Walter,
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