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Performance hit after upgrading MySQL4.0 to 4.1
Posted by: Wolfgang Blauen
Date: March 02, 2005 11:40AM

I am having a performance problem with an existing application written in VB6.
The application uses the ODBC (3.51) connector to retreive data from and update data in a MySQL database that was created in version 4.0.1 .
After an upgrade to Version 4.1.0 (and/or 4.1.10) the application has significant performance problems.
I have tested all hardware, OS and Network components and the server performs perfectly.
All tables are myISAM type with a mixture of fixed and dynamic row types.

Has anyone else had this problem and is there potentially a protocol change in 4.1 that slows down the data transfer or causes the ODBC driver to return bogus data?
Another problem that showed up is that there seems to be some cross linking between records. i.e: "Select name, number from service where extrefno=436;" returns an emty recordset while "Select name, number from service where extrefno>435 and extrefno<437;" returns the correct record (only ole exists in the table). An update query with the "... where extrefno=436 ... " clause resports 37 updated records (should be 1). Similar things happen on deletes. "Repair table ... extended" or "myisamcheck ..." do not find any problems.

What's the deal?

Any input is appreciated. Thanks in advance.

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Performance hit after upgrading MySQL4.0 to 4.1
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March 02, 2005 11:40AM


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