FIX: Connection pooling causes Windows 2000 computer with MDAC 25/2.5 SP1 to stop responding (294140)

MORE INFORMATION

Steps to reproduce behavior

1. Create a new Visual C++ Console application and paste the following code into a .cpp file:

   
   #include <iostream.h>
   #include <windows.h>
   #include <SQL.h>
   #include <SQLEXT.h>
   #include <ODBCINST.h>
   #include <stdio.h>
   #include <process.h>
   #define MAXBUFLEN 255
   
   unsigned __stdcall TestPooling(LPVOID pParam);
   void	ProcessLogMessages(SQLSMALLINT plm_handle_type,
   						   SQLHANDLE plm_handle, char *logstring);
   HENV g_henv;
   
   
   
   DWORD g_dwIterations = 10;
   DWORD g_dwWorkerThreads = 2;
   
   int main(int argc, char **argv)
   {
           DWORD mydata;
           SQLRETURN nSQLRetCode = SQLSetEnvAttr(SQL_NULL_HENV,  SQL_ATTR_CONNECTION_POOLING, (void*)SQL_CP_ONE_PER_DRIVER, 0);
   	
   	nSQLRetCode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HENV, &g_henv);
   	
   	nSQLRetCode = SQLSetEnvAttr(g_henv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, SQL_IS_INTEGER);
   	
   		
   	cout	<< "Enter number of worker threads:";
   	cin		>> g_dwWorkerThreads;
   
   	cout	<< "Enter no of iterations:";
   	cin		>> g_dwIterations;
   
   	int nDelay = 0;
   	cout	<< "Delay:";
   	cin		>> nDelay;
   
   	HANDLE *pThreadHandles = new HANDLE[g_dwWorkerThreads];
   
   	unsigned int dwThreadId = 0;
   	for ( DWORD i = 0; i < g_dwWorkerThreads; i++)
   	{
   		pThreadHandles[i] = (HANDLE)_beginthreadex(NULL,0,TestPooling, NULL, 0, &dwThreadId );
   		printf("Creating thread<%d><%d>\n", i, dwThreadId);
   		
   		if ( nDelay > 0 )
   		{
   			Sleep(nDelay); 
   		}
   	
   	}
   	
   	printf("Waiting for worker threads to finish\n");
   
   	
   	mydata= WaitForMultipleObjects(g_dwWorkerThreads,pThreadHandles,TRUE,INFINITE);
   
   	printf("Done waiting for worker threads to finish!\n");
   	getchar();
   
       return (0);
   }
   
   unsigned __stdcall TestPooling(LPVOID pParam)
   {
   	SQLRETURN nSQLRetCode = SQL_SUCCESS;
   
   	SQLHDBC		m_hdbc;
   	char buffer[256];
   	
   	TCHAR tConnectionStringIn[ 256 ], tConnStringOut[256];
   	SWORD	cLength = 0;	SDWORD	cbTemp = 0;	SQLRETURN nRetCode =SQL_SUCCESS;
   
   	for ( DWORD i = 0; i < g_dwIterations; i++ )
   	{
   		do
   		{
   			nSQLRetCode = SQLAllocHandle(SQL_HANDLE_DBC, g_henv, &m_hdbc);
   			if ( SQL_ERROR == nSQLRetCode )
   			{
   				printf("Allocating connection handle failed");
   				break;
   			}
   	
   			sprintf(	tConnectionStringIn,  
   						"DRIVER={SQL Server};SERVER=%s;UID=%s;PWD=%s;DATABASE=%s;APP=%s",
   						"TestMSSQLServer", "sa","","pubs","pooltest");
   		         sprintf(buffer,"This is thread 0x%08x. before SQLDriverconnect .\n",GetCurrentThreadId());
   			OutputDebugString(buffer);
   
   			
   			nSQLRetCode = SQLDriverConnect(m_hdbc, NULL, (SQLTCHAR*) tConnectionStringIn,strlen( tConnectionStringIn ),
                                                         (SQLTCHAR*) tConnStringOut,(SWORD)(sizeof(tConnStringOut)/sizeof(TCHAR)),
                                                         &cLength, SQL_DRIVER_NOPROMPT);	//connect to the odbc
   			
   		         if (nSQLRetCode == SQL_ERROR)
   		         {
   	   	            ProcessLogMessages(SQL_HANDLE_DBC, m_hdbc, "SQLConnect() Failed\n\n");
   	   	           break;
   		         }
   	
   
   			sprintf(buffer,"This is thread 0x%08x.after  SQLDriverConnect \n",GetCurrentThreadId());
   		         OutputDebugString(buffer);
   
   
   			SQLDisconnect(m_hdbc);	
   			sprintf(buffer,"This is thread 0x%08x.after SQLDisconnect\n",GetCurrentThreadId());
          		         OutputDebugString(buffer);
   
   			SQLFreeHandle(SQL_HANDLE_DBC, m_hdbc);	
   			sprintf(buffer,"This is thread 0x%08x. after SQLFreeHandle dbc\n",GetCurrentThreadId());
   			OutputDebugString(buffer);   
   	
   		} while ( FALSE );
   	}
   
   	printf("<%d>Done\n",GetCurrentThreadId());
   
   	return 100;
   }
   
   void ProcessLogMessages(SQLSMALLINT plm_handle_type, SQLHANDLE plm_handle,
   						char *logstring)
   {
   	RETCODE		plm_retcode = SQL_SUCCESS;
   	UCHAR		plm_szSqlState[MAXBUFLEN] = "",plm_szErrorMsg[MAXBUFLEN] = "";
   	SDWORD		plm_pfNativeError = 0L;
   	SWORD		plm_pcbErrorMsg = 0;
   	SQLSMALLINT	plm_cRecNmbr = 1;
   
   	printf(logstring);	
   
   	while (plm_retcode != SQL_NO_DATA_FOUND)
   	{
   		plm_retcode = SQLGetDiagRec(plm_handle_type, plm_handle,
   			plm_cRecNmbr, plm_szSqlState, &plm_pfNativeError,
   			plm_szErrorMsg, MAXBUFLEN - 1, &plm_pcbErrorMsg);
   		if (plm_retcode != SQL_NO_DATA_FOUND)
   		{
   			printf("szSqlState = %s\n",plm_szSqlState);
   			printf("pfNativeError = %d\n",plm_pfNativeError);
   			printf("szErrorMsg = %s\n",plm_szErrorMsg);
   			printf("pcbErrorMsg = %d\n\n",plm_pcbErrorMsg);
   		}
   		plm_cRecNmbr++;
   	} // end while
   }
   					

2. Compile and run the project.