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Conference orarep::nomahs::odbc_rdb_driver

Title:DEC ODBC Driver
Notice:DEC ODBC Driver V2.0 Now Available
Moderator:SQLSRV::MAVRIS
Created:Tue Dec 29 1992
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1357
Total number of notes:4864

1313.0. "FetchAhead=NO and MS-VB/Access ?" by NOMAHS::SECRIST (Rdb WWS; rsecrist@us.oracle.com) Fri Mar 21 1997 13:05

    
    	Oracle recommends that FetchAhead=NO with Developer/2000 1.3.
    	Should this be the case with typical Visual Basic or MS-Access
    	usage (with or without SQLPASSTHROUGH) ?
    
    	Regards,
    	rcs
    
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1313.1M5::JHAYTERFri Mar 21 1997 13:166
>    	Oracle recommends that FetchAhead=NO with Developer/2000 1.3.
>    	Should this be the case with typical Visual Basic or MS-Access
>    	usage (with or without SQLPASSTHROUGH) ?

No

1313.2application dependant...M5::JBALOGHFri Mar 21 1997 13:5124
    FetchAhead enables a feature that allows SQLServices to fetch more than
    1 row per network packet. It essentially tells the driver to use
    SQL_FETCH_MANY calls instead of individual fetches.
    
    This is the same functionality as the ODBC SQLExtendedFetch call. Many
    front end applications do not use the more efficiant SQLExtendedFetch
    call so FetchAhead is a way to override that to improve performance. 
    
    There are a couple cases where you would not want fetchahead enabled. The
    first is if the application has more than 1 statement active on a
    connection at a time. For example, if an app is fetching from a
    previously prepared statement and tries to prepare/execute another
    select statement on the same connection while the original is still
    active. In this case, the driver returns a pretty descriptive error
    indicating this (something like can't do this with fetchahead enabled). 
    
    Another would be if your network was flaky. I have seen occurances of
    weird packet problems that go away when FetchAhead is disabled.
    
    In any case, this feature can dramaticly improve performance and I
    would only turn it off if necessary. 
    
    John