I would like to ask if anyone knows a workaround to our problem. The problem is bad performance due to a problem with Opportunistic Locking in some Windows versions, and is documented in this knowledge base article:

http://support.microsoft.com/?kbid=306981

Whilst not on the list, we verified that this problem persists on Windows 2000 Server SP4 as well.

The problem is that our ISAM database driver uses LockFileEx to lock parts of the database index files, which in effect will mark this file as "non-oplockable" as soon as the first concurrent access occurs. I understand that this LockFileEx call is probably unavoidable because the files are opened in shared mode to allow write access for concurrent clients to the same database.

We are already trying to get our hands on an improved ISAM database driver, but if LockFileEx is unavoidable this would provide no benefit for us. Accessing the database files locally is also out of question, unfortunately.

Are there any fixes or workarounds to this problem? Do you know any Microsoft Windows Server versions which aren't affected?

Any help would be appreciated.