BUG: Async Keyset Cursors and Memory Pressure May Cause AV and Server Shutdown

ID: Q226154

The information in this article applies to:

Microsoft SQL Server version 7.0

BUG #: 55013 (SQLBUG_70)

SYMPTOMS

If users are executing asynchronous keyset cursors while SQL Server is under memory pressure, a handled access violation (AV) and/or a runtime error that ends the SQL Server process may occur.

The client application may be returned one of the following errors before the access violation or shutdown of the server:

Error: 16942
Could not generate asynchronous keyset. The cursor has been deallocated.

-or-

Error: 16917
Cursor is not open.

WORKAROUND

To work around this problem, disable asynchronous keyset cursors by changing the 'cursor threshold' configuration value to -1 (which is the default).

You also may be able to avoid this problem by increasing the memory available to SQL Server or by reducing memory consumption of other applications on the SQL Server.

STATUS

Microsoft has confirmed this to be a problem in SQL Server version 7.0.

MORE INFORMATION

The following errors and stack trace may be seen in the error log when encountering this problem:


Short Stack Dump
0x005aec8e Module(sqlservr+1aec8e) (CCursorXCFetch::ResetPoplThreadLocalStore+d)
0x005aeba6 Module(sqlservr+1aeba6) (CCursorXCFetch::ResetScan+1d)
0x0059c046 Module(sqlservr+19c046) (CCursor::Close+b6)
0x0059bf5e Module(sqlservr+19bf5e) (CCursor::Open+145)
0x00599ae7 Module(sqlservr+199ae7) (CCursorSimpleStmt::XretExecute+a1)
0x00419efa Module(sqlservr+19efa) (CMsqlExecContext::ExecuteStmts+118)
0x00419a0f Module(sqlservr+19a0f) (CMsqlExecContext::Execute+16b)


Error occurred during cursor close.
Error occurred during cursor cleanup.

The server may also shut down prematurely when encountering this problem. If SQL Server is running as a service, the error log will contain no indication of why the shutdown occurred.

If SQL Server is running from the console, the following message will be dumped to the console before the shutdown:

runtime error R6025
- pure virtual function call

Additional query words: async asynch terminate terminates terminated killed errorlog

Keywords : kbbug7.00
Version : winnt:7.0
Platform : winnt
Issue type : kbbug