Article ID: 164215
Article Last Modified on 8/10/2006
APPLIES TO
- Microsoft SQL Server 6.5 Standard Edition
This article was previously published under Q164215
BUG #: 16556 (6.5)
SYMPTOMS
Sp_cursoropen generates an access violation (AV) in xpcursordeclare (on a checked server) or breaks the connection (on a retail server) if you do all of the following:
- Open an extended KEYSET_DRIVEN or INSENSITIVE extended cursor on a stored procedure that references a table containing a unique clustered index, non-clustered index, or primary key (PK) constraint.
- Close the cursor.
- Drop the index or constraint.
- Open the cursor again.
The symptom of the broken connection is usually a "bad token" message returned to the client. Slight variations of this may cause an AV in cursornewrow on a checked (or debug) server.
An extended KEYSET_DRIVEN cursor is exposed at the DB-Library API layer as CUR_KEYSET in dbcursoropen() and at the ODBC API layer as SQL_CURSOR_KEYSET_DRIVEN in SQLSetStmtOption(). An extended INSENSITIVE cursor is exposed at the DB-Library layer as CUR_INSENSITIVE in dbcursoropen(), and at the ODBC API layer as SQL_CURSOR_STATIC in SQLSetStmtOption().
WORKAROUND
To work around this problem, do any of the following:
- Use a different cursor type.
- Use trace flag -T7502 to "Disable caching cursor plans in procedure cache."
- Create the stored procedure WITH RECOMPILE.
- Drop and re-create the stored procedure after making a table schema change.
STATUS
Microsoft has confirmed this to be a problem in Microsoft SQL Server version 6.5. This problem has been corrected in U.S. Service Pack 3 for Microsoft SQL Server version 6.5. For more information, contact your primary support provider.
MORE INFORMATION
SQL Server supports two different server-side cursor interfaces. One is ANSI SQL cursors, which are exposed through Transact-SQL statements such as DECLARE, FETCH, and so on. The other cursor interface is an extended cursor interface that is accessed through the DB-Library and ODBC APIs. The sp_cursor extended cursor statements are emitted by the DB-Library or ODBC layers in response to certain DB-Library or ODBC API calls. Higher- level interfaces such as Remote Data Objects (RDO) will often encapsulate these API-level calls, so you would need to run a trace utility such as SQL Trace to verify the sp_cursor call being made.
Keywords: kb3rdparty kbbug kbfix kbhardware KB164215