OpenEdge Data Management: DataServer for Microsoft SQL Server

Troubleshooting
8–8
For example, the following connection string sets the user ID and password for the server
and user ID and password for the data source:
DSN=sports;UID=engine-login-name;PWD=engine-login-pass;UIDDBMS=dblogin;
PWDDBMS=dblogin-pass
For more information and syntax examples, see the “Special connection issues” section on
page 6–14.
Key-buffer size—the PRGRS_IDBUF option
The PRGRS_IDBUF option sets the size of the keys buffer. Generally, a default of 25 keys is
sufficient. If the ODBC driver being used to access the MS SQL Server database has preserved
cursors enabled across a transaction boundary, the keys buffer is used with all non-lookahead
cursors. If the driver does have preserved cursors enabled, the PROGRS_IDBUF value and the keys
buffer are unused.
Locking error messages—the PRGRS_LOCK_ERRORS option
DataServer for MS SQL Server identifies and handles conditions and errors. However, the
PRGRS_LOCK_ERROR option lets you control how your application reacts if it encounters an error
that is actually a lock problem when accessing a data source. Use this option to pass the native
error number to the DataServer so that it handles this error as it would an OpenEdge database
lock problem; that is, the DataServer waits and retries, rather than halting the application:
CONNECT data-source-name -ld logical-name -dt mss
-Dsrv PRGRS_LOCK_ERRORS,error-number1,error-number2.
Large rows—the PRGRS_MINBUF option
Some data rows can be very large; for example, in a MS SQL Server database, rows often have
large fields such as IMAGE and MEMO. The ODBC protocol specifies a dynamic buffer allocation
process for handling large rows that do not initially fit into clients’ buffers; however, some
drivers do not yet follow the correct ODBC protocol and do not handle these large rows
correctly. Use the -Dsrv PRGRS_MINBUF,size option to force a minimum buffer size. For
example, -Dsrv PRGRS_MINBUF,15000 enables the DataServer to handle 15K rows even with
drivers that fail to follow the ODBC protocol.
The optimal setting for PRGRS_MINBUF is the size of the largest record data size plus 500 bytes.
This can prevent run-time record expansion during the retrieval of query results.
Notes: Do not use this option when the -Dsrv BINDING switch is set to 3. With the binding set
to 3, the size of the data is known, and this switch will cause the allocation of unneeded
additional memory.
It is often difficult to determine when there is a buffer size problem and how to choose
the correct value for PRGRS_MINBUF. Be careful when using this option.