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How much data moves from Server to Client?
Message
De
04/12/1999 19:25:32
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00298027
Message ID:
00298798
Vues:
19
>>This is absolutely not true. I have several tables that reside on server that approach a gig in size, and opening them takes no longer than opening a small table.
>
>I also have no trouble opening tables (regardless of the size) on the LAN. So what is your explanation for the several minutes that it takes (equivalent to downloading the table) to open a table over a slow connection, whether with the USE command or ODBC SQL (to retrieve one record). On my 56K WAN it takes about a minute for a small table and then more time depending on the size of the table.
>

I don;t know the details of what comes over the wire, I just know that it can't be the entire table. To test this, open a larger table over your slow connection, and notice that it doesn't take any longer than the first one. I have opened 100MB tables over a 56K connection, and it did not take several hours like it would if the entire table was actually going over the line.


>Without a back-end server (or COM) serving up the data how can VFP manipulate a table or index without having access to the entire table? As soon as I do a SQL Select it needs access to the entire table (or at least the entire table when it has to build an index on the fly).

I won't contest this. SQL SELEWCT is extremely slow over a slow connection. To do this, you really need to connect to a server database, or have code running on the server (DCOM, ISAPI, whatever).
Erik Moore
Clientelligence
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