Q175313: BUG: S1000 Error When Sharing Connection in Multiple Threads
Article: Q175313
Product(s): Open Database Connectivity (ODBC)
Version(s): 2.0,3.0,5.0,6.0
Operating System(s):
Keyword(s): kbDatabase kbMFC kbODBC kbSQLServ kbVC500 kbGrpDSMDAC kbDSupport kbGrpDSODBC
Last Modified: 14-JUN-2001
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The information in this article applies to:
- Microsoft ODBC Driver for SQL Server, versions 2.0, 3.0
- Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0
- Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0
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SYMPTOMS
========
When you share a CDatabase object between multiple threads and use the SQL
Server ODBC driver version 2.65.0240 or later, you may receive the following
error message:
SQLSTATE: S1000
[Microsoft][ODBC SQL Server Driver]Connection is busy with the results for
another hstmt
When you use the Microsoft Data Access Components (MDAC) 2.6 driver, you may
receive the following error message:
State:37000,Native:16909,Origin:[Microsoft][ODBC SQL Server Driver][SQL
Server]
sp_cursorfetch: The cursor identifier value provided (1) is not valid
CAUSE
=====
This error occurs because of a timing conflict in the SQL Server ODBC driver or
MDAC 2.6 driver. If two threads are in the process of calling SQLPrepare(),
followed by a SQLExecute() call, this error may occur.
RESOLUTION
==========
Put CRecordset::Open() calls within a critical section to guarantee that only
one thread is executing a SQL command on the connection at a given time.
On the SQL Server back end, it is recomended that you use different CDatabase
objects for different threads.
STATUS
======
Microsoft has confirmed this to be a bug in the Microsoft SQL Server driver.
MORE INFORMATION
================
Following is a code sample that can cause this error to occur:
Sample code
-----------
void CDBProblemDlg::OnDoDatabase()
{
//Open connection to database
m_DB.Open();
CSQLRecordSet rs(&m_DB);
StartThread(&m_DB);
if ( rs.Open(CRecordset::dynaset) )
{
.
.
.
SQLRecordSet.Close();
}
}
void StartThread(CDatabase * pDB)
{
AfxBeginThread(InitThreadProc, pDB, THREAD_PRIORITY_NORMAL);
}
UINT CDBProblemDlg::InitThreadProc( LPVOID pParam )
{
CDatabase* pDB = (CDatabase*) pParam;
if (pDB->IsOpen())
{
CSQLRecordSet SQLRecordSet(pDB);
if (SQLRecordSet.Open(CRecordset::dynaset))
{
.
.
.
SQLRecordSet.Close();
}
}
}
Additional query words: VC++
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Keywords : kbDatabase kbMFC kbODBC kbSQLServ kbVC500 kbGrpDSMDAC kbDSupport kbGrpDSODBC
Technology : kbVCsearch kbSQLServSearch kbAudDeveloper kbODBCSearch kbODBCSQLServ200 kbODBCSQLServ300 kbVC500 kbVC600 kbVC32bitSearch kbVC500Search
Version : :2.0,3.0,5.0,6.0
Issue type : kbbug
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