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Packing a file
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19/02/2007 18:08:47
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Titre:
Versions des environnements
Visual FoxPro:
VFP 7
Divers
Thread ID:
01197163
Message ID:
01197166
Vues:
14
Hi Rich,

There're 2 reasons to delete all indexes before adding a lot of data to a table:

  • Performance. The existing indexes have to be updated during append which will slow down the process.
  • Index bloat. See http://fox.wikis.com/wc.dll?Wiki~CDXBloat

    >We have a huge file which regularly approaches the 2GB limit. The system is being rewritten to use an Oracle back-end but needs regular TLC in the interim.
    >
    >The procedures here are to
    >
    >1. Save the index tags to an array
    >2. Copy the older records to a temp table
    >3. Delete those records
    >4. Delete all the index tags
    >5. PACK the tables (should bring the size down from 1.9 GB to 1.6 GB)
    >6. Rebuild each index tag separately from the array
    >
    >The archive file is also growing rather large (1.25 GB at the moment). Prior to APPENDing from the temp table, they also DELETE the index tags and then rebuild them.
    >
    >There are anywhere from 10 to 30 tags involved on the tables involved in this process.
    >
    >Is there any performance or safety reason for doing this? Are there any reasons to avoid doing something like this?
    --sb--
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