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Dbf size and LAN performance
Message
De
07/07/1999 17:21:36
Mike Yearwood
Toronto, Ontario, Canada
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00238375
Message ID:
00238550
Vues:
14
I've heard of people with the concept that the entire file got transmitted, but I've never met one <g>. If you're running Novell, you can determine that the entire file is not being sent to the workstation. If it was, you'd already be having incredible performance problems. This does happen in backend environments if parameterized views are not employed.

Fox (and incidentally dBase and Clipper) only bring a part of any file to a workstation. Unlike SQL/Oracle, you're not in complete control of exactly what is transmitted. Fox fetches some records for buffering purposes. When you SEEK "YEARWOOD", it skips through the CDX file in small pieces, until it gets to "YEARWOOD" then it gets the record number and brings at least that record down the wire.

Rushmore has to transmit the entire index tag down the wire, but since tags are so much smaller than the entire data record, its happens relatively quickly.
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