FIX: Memory Leak in Jet ODBC Driver with SQL_NUMERIC or SQL_C_BINARY Data

• To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
  260910 How to Obtain the Latest Windows 2000 Service Pack
• To resolve this problem, obtain the latest service pack for Microsoft Data Access Components 2.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
  293312 INFO: How to Obtain the Latest MDAC 2.5 Service Pack

   Date        Version       Size              File name    
   ---------------------------------------------------------------------
   09/13/00    4.0.5708.0    270,608 bytes    Odbcjt32.dll
   09/14/00    1.10.101.0    295,696 bytes    Q273772_W2K_SP2_x86_en.EXE
				

WORKAROUND

Steps to Reproduce Behavior

1. Copy the code that follows into a Microsoft Visual C++ console application, and then compile the code. Please note that you may need to change the datasource name, user id and password.

   #include <windows.h>
   #include <sql.h>
   #include <sqlext.h>
   #include <tchar.h>
   #include <stdlib.h>
   #include <stdio.h>
   
   
   #define LEAK_NUMERIC 1		//Use this to determine NUMERIC or BINARY leak
   
   
   void HandleError(SQLHANDLE	hHandle, SQLSMALLINT hType, RETCODE RetCode)
   {
   	SQLSMALLINT	iRec = 0;
   	SQLINTEGER	iError;
   	TCHAR		szMessage[1000];
   	TCHAR		szState[SQL_SQLSTATE_SIZE];
   
   
   	if (RetCode == SQL_INVALID_HANDLE)
   	{
   		fprintf(stderr,"Invalid handle!\n");
   		return;
   	}
   
   	while (SQLGetDiagRec(hType,
   			 hHandle,
   			 ++iRec,
   			 (SQLCHAR *)szState,
   			 &iError,
   			 (SQLCHAR *)szMessage,
   			 (SQLSMALLINT)(sizeof(szMessage) / sizeof(TCHAR)),
   			 (SQLSMALLINT *)NULL) == SQL_SUCCESS)
   	{
   		fprintf(stderr,TEXT("[%5.5s] %s (%d)\n"),szState,szMessage,iError);
   	}
   
   }
   
   
   char* szConnStringIn = "Driver={Microsoft Access Driver (*.mdb)};DBQ=E:\\JetLeak\\TestDatabase.mdb";
   char* szDropTable = "DROP TABLE LeakTable";
   //char* szInsertStatement = "INSERT INTO LeakTable VALUES (?)";
   char* szSelectStatement = "SELECT * FROM LeakTable WHERE val1 = ?";
   const int nParamCount = 1; 
   
   #if LEAK_NUMERIC
   char* szCreateTable = "CREATE TABLE LeakTable (val1 long)";
   #else
   char* szCreateTable = "CREATE TABLE LeakTable (val1 varchar(10))";
   #endif
   
   
   
   void main(int argc, char* argv[])
   {
   	SQLHENV henv;
   	SQLHDBC hdbc;
   	SQLHSTMT hstmt;
   	SQLRETURN nstatus;
   
   	char szConnStringOut[1024];
   	SQLSMALLINT cbConnOut;
   	SQLINTEGER status[nParamCount];
   
   #if LEAK_NUMERIC
   	SQLCHAR szParam[nParamCount][10] = {"12345"};
   #else
   	BYTE szParam[nParamCount][10] = {0x31,0x33,0x34,0x39};
   #endif
       
   	//Not checking the return codes in some cases for clarity.
   	
   	nstatus = SQLAllocHandle(SQL_HANDLE_ENV,NULL,&henv);
   	nstatus = SQLSetEnvAttr(henv,SQL_ATTR_ODBC_VERSION,(SQLPOINTER) SQL_OV_ODBC3,0);
   	nstatus = SQLAllocHandle(SQL_HANDLE_DBC,henv,&hdbc);
   
   	nstatus = SQLDriverConnect(hdbc,
   			NULL,
   			(SQLCHAR*) szConnStringIn,
   			SQL_NTS,
   			(SQLCHAR*) szConnStringOut,
   			sizeof (szConnStringOut),
   			&cbConnOut,
   			SQL_DRIVER_COMPLETE);
   							
   	if (nstatus != SQL_SUCCESS && nstatus != SQL_SUCCESS_WITH_INFO)
   	{
   		HandleError(hdbc,SQL_HANDLE_DBC,nstatus);
   		return;
   	}
   
   	nstatus = SQLAllocHandle(SQL_HANDLE_STMT,hdbc,&hstmt);	
   
   	nstatus = SQLExecDirect(hstmt, (SQLCHAR*) szDropTable, SQL_NTS);
   	nstatus = SQLExecDirect(hstmt, (SQLCHAR*) szCreateTable, SQL_NTS);
   
   	if (!SQL_SUCCEEDED(nstatus))
   	{
   		HandleError(hstmt,SQL_HANDLE_STMT,nstatus);
   	}
   
   	int i;
   	//only one parameter in this case
   	for (i=0; i < nParamCount; i++)
   	{
   		status[i] = SQL_NTS;
   
   
   
   #if LEAK_NUMERIC
   		nstatus = SQLBindParameter(hstmt,
   			i+1,
   			SQL_PARAM_INPUT,
   			SQL_C_CHAR,	
   			SQL_NUMERIC, 
   			10, 
   			0,
   			szParam[i],
   			10,
   			&status[i]);
   #else
   
   		nstatus = SQLBindParameter(hstmt,
   			i+1,
   			SQL_PARAM_INPUT,
   			SQL_C_BINARY,	
   			SQL_WCHAR,
   			10, 
   			0,
   			szParam[i],
   			10,
   			&status[i]);
   #endif
   	
   	
   	}
   
   	nstatus = SQLPrepare(hstmt,(SQLCHAR*) szSelectStatement, SQL_NTS);
   	if (nstatus != SQL_SUCCESS)
   	{
   		HandleError(hstmt,SQL_HANDLE_STMT,nstatus);
   	}
   
   	for (i=0; i < 100000; i++)
   	{
   		if (i % 100 == 0)
   		{
   			printf("Selected %d times\n", i);
   			//printf("Inserted %d records\n", i);
   			Sleep(100);
   		}
   		nstatus = SQLExecute(hstmt);
   		if (nstatus != SQL_SUCCESS)
   		{
   			HandleError(hstmt,SQL_HANDLE_STMT,nstatus);
   		}
   
   		SQLFreeStmt(hstmt, SQL_CLOSE);
   	}
   
   	nstatus = SQLExecDirect(hstmt, (SQLCHAR*) "DELETE FROM LeakTable", SQL_NTS);
   	if (nstatus != SQL_SUCCESS)
   	{
   		HandleError(hstmt,SQL_HANDLE_STMT,nstatus);
   	}
   
   	SQLFreeStmt(hstmt, SQL_CLOSE);
   	SQLDisconnect(hdbc);
   
   }
   
   						

   NOTE: You can use the LEAK_NUMERIC constant to demonstrate either the SQL_NUMERIC or SQL_C_BINARY leak.
2. Create a new blank Microsoft Access database as specified by the location in your connection string.
3. Start running the code, and then use Performance Monitor to watch the Private Bytes counter for the process.
   
   Note that the Private Bytes counter rises steadily while the code is running.