Description:
It seems there is a bug in the MySQL ODBC driver 03.51.20 with the MySQL Server 5.1.22. This MySQL ODBC driver or the server allows dirty reading even after the isolation level is set to SQL_TXN_READ_COMMITTED with the following ODBC API
SQLINTEGER isolation = SQL_TXN_READ_COMMITTED;
ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)(a_ptrint)isolation, SQL_IS_UINTEGER );
I have two apps: app 1 issues inserts to a table named test (without commit) and then goes to sleep and app 2 fetches rows from the test table when the first app is sleeping. I can see app 2 will fetch all the rows inserted by app 1, even app 1 did not commit the transaction.
This problem still happens even my table is created with the clause, "engine=InnoDB".
Please note: the driver and server work well if my ODBC app uses the default isolation level, I believe that is SQL_TXN_REPEATABLE_READ with the MySQL ODBC driver 3.51.20
Here is my source code for app 1:
void ShowBug( p_ml_host_conn conn )
/*********************************/
{
SQLHSTMT stmt;
RETCODE ret;
char * drop = "drop table test";
char * create = "create table test( c1 int primary key, c2 int ) engine InnoDB";
char * insert = "insert into test values( 1, 1 )";
SQLINTEGER isolation = SQL_TXN_READ_COMMITTED;
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_AUTOCOMMIT,
(SQLPOINTER)SQL_AUTOCOMMIT_OFF,
SQL_IS_UINTEGER );
_c( conn->host->env, conn->dbc, NULL );
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_TXN_ISOLATION,
(SQLPOINTER)(a_ptrint)isolation,
SQL_IS_UINTEGER );
_c( conn->host->env, conn->dbc, NULL );
ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLExecDirect( stmt, (SQLCHAR *)drop, SQL_NTS );
ret = SQLExecDirect( stmt, (SQLCHAR *)create, SQL_NTS );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLExecDirect( stmt, (SQLCHAR *)insert, SQL_NTS );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt );
_c( conn->host->env, conn->dbc, stmt );
printf( "I am sleeping ...\n" );
Sleep( 20000 );
printf( "I am rolling back the tran\n" );
ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK );
done:
return;
}
and the source code for app 2:
void ShowBug( p_ml_host_conn conn )
/*********************************/
{
SQLHSTMT stmt;
RETCODE ret;
char * select = "select c1, c2 from test";
SQLINTEGER c1;
SQLINTEGER c2;
SQLINTEGER c1_ind;
SQLINTEGER c2_ind;
SQLINTEGER isolation = SQL_TXN_READ_COMMITTED;
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_AUTOCOMMIT,
(SQLPOINTER)SQL_AUTOCOMMIT_OFF,
SQL_IS_UINTEGER );
_c( conn->host->env, conn->dbc, NULL );
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_TXN_ISOLATION,
(SQLPOINTER)(a_ptrint)isolation,
SQL_IS_UINTEGER );
_c( conn->host->env, conn->dbc, NULL );
ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLPrepare( stmt, (SQLCHAR *)select, SQL_NTS );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLBindCol( stmt, 1, SQL_C_SLONG, &c1, sizeof( c1 ), &c1_ind );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLBindCol( stmt, 2, SQL_C_SLONG, &c2, sizeof( c2 ), &c2_ind );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLExecute( stmt );
_c( conn->host->env, conn->dbc, stmt );
while( ( ret = SQLFetch( stmt ) ) != SQL_NO_DATA ) {
printf( "ret = %d c1 = %d, c1_ind = %d, c2 = %d, c2_ind = %d\n",
ret, c1, c1_ind, c2, c2_ind );
}
ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt );
_c( conn->host->env, conn->dbc, stmt );
ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK );
done:
return;
}
How to repeat:
Build two applications with the attached source code: compile one with -DINSERT and the second one without this flag. Then run app 1 and app2 consecutively and then you'll see app 2 will show the un-committed insert. The command line to start app1 or app2 could be
odbcbug.exe "dsn=mydsn;uid=myuid;pwd=mypassword"
Here is the source code:
----------------------------------------------------------------------
// ODBCBugs.C - Simple ODBC skeleton for duplicating ODBC bugs
// that can't be duplicated using ODBC Test.
// The function called ShowBug() duplicates the problem.
// To run the test, the first parameter must be an ODBC connection string
// in quotes:
//
// odbcbug "dsn=mydsn;uid=myuid;pwd=mypwd"
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include <process.h>
#include "odbc.h"
#if ODBCVER < 0x0350
#error "***** This module requires ODBC 3.5 or higher *****"
#endif
typedef unsigned int uint32;
typedef uint32 _W64 a_ptrint;
typedef struct an_odbc_info {
SQLHENV env;
} an_odbc_info, *p_odbc_info;
typedef struct an_odbc_conn {
p_odbc_info info;
SQLHDBC dbc;
int kill;
int done;
} an_odbc_conn, *p_odbc_conn;
#define _c( e, d, s ) \
if( ret != 0 && ret != SQL_SUCCESS_WITH_INFO ) { \
printf( "error at line: %d\n", __LINE__ ); \
ODBC_error( e, d, s ); \
goto done; \
}
void ODBC_error( HENV henv, HDBC hdbc, HSTMT hstmt )
/**************************************************/
{
UCHAR sqlstate[10];
UCHAR errmsg[SQL_MAX_MESSAGE_LENGTH];
SDWORD nativeerr;
SWORD actualmsglen;
RETCODE rc;
loop: rc = SQLError( (SQLHENV)henv, (SQLHDBC)hdbc, (SQLHSTMT)hstmt,
sqlstate, &nativeerr, errmsg,
SQL_MAX_MESSAGE_LENGTH - 1, &actualmsglen );
if( rc == SQL_ERROR) {
printf( "SQLError failed!\n");
return;
}
if( rc != SQL_NO_DATA_FOUND ) {
printf( "SQLSTATE = %s\n", sqlstate );
printf( "NATIVE ERROR = %d\n", nativeerr );
errmsg[actualmsglen] = '\0';
printf( "MSG = %s\n\n", errmsg );
goto loop;
}
}
p_odbc_info Init( void )
/**********************/
{
p_odbc_info info;
RETCODE ret;
info = (p_odbc_info) malloc( sizeof( *info ) );
if( info != NULL ) {
ret = SQLAllocHandle( SQL_HANDLE_ENV, SQL_NULL_HANDLE, &info->env );
_c( info->env, NULL, NULL );
ret = SQLSetEnvAttr( info->env,
SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0 );
_c( info->env, NULL, NULL );
}
done:
return( info );
}
void Fini( p_odbc_info info )
/***************************/
{
RETCODE ret;
// Clean up any resources and shut the module down.
if( info->env != SQL_NULL_HENV ) {
ret = SQLFreeHandle( SQL_HANDLE_ENV, info->env );
}
}
p_odbc_conn Connect(
/******************/
p_odbc_info info,
char * conn_str )
{
// Establish a connection with the host database. This may
// create a new connection or just grab one from a pool
// of connections.
p_odbc_conn conn;
SQLSMALLINT conn_str_len;
char out_str[ 2048 ];
RETCODE ret = SQL_ERROR;
conn = (p_odbc_conn) malloc( sizeof( an_odbc_conn ) );
if( conn == NULL ) {
goto done;
}
conn->info = info;
conn->dbc = SQL_NULL_HDBC;
conn->done = FALSE;
ret = SQLAllocHandle( SQL_HANDLE_DBC, info->env, &conn->dbc );
_c( info->env, conn->dbc, NULL );
ret = SQLDriverConnect( conn->dbc,
NULL, // HWND_NULL,
(SQLCHAR *)conn_str,
SQL_NTS,
(SQLCHAR *)out_str,
sizeof( out_str ),
&conn_str_len,
SQL_DRIVER_NOPROMPT );
_c( info->env, conn->dbc, NULL );
if( ( ret != SQL_SUCCESS ) && ( ret != SQL_SUCCESS_WITH_INFO ) ) {
conn = NULL;
goto done;
}
// Use transactions instead of auto-commit
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_AUTOCOMMIT,
(SQLPOINTER)SQL_AUTOCOMMIT_OFF,
SQL_IS_UINTEGER );
_c( info->env, conn->dbc, NULL );
done:
return( conn );
}
void Disconnect( p_odbc_conn conn )
/*********************************/
{
if( conn != NULL ) {
if( conn->dbc != SQL_NULL_HDBC ) {
SQLDisconnect( conn->dbc );
SQLFreeHandle( SQL_HANDLE_DBC, conn->dbc );
}
free( conn );
}
}
#ifdef INSERT
void ShowBug( p_odbc_conn conn )
/******************************/
{
SQLHSTMT stmt;
RETCODE ret;
char * drop = "drop table test";
char * create = "create table test( c1 int primary key, c2 int ) engine=InnoDB";
char * insert = "insert into test values( 1, 1 )";
SQLINTEGER isolation = SQL_TXN_READ_COMMITTED;
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_AUTOCOMMIT,
(SQLPOINTER)SQL_AUTOCOMMIT_OFF,
SQL_IS_UINTEGER );
_c( conn->info->env, conn->dbc, NULL );
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_TXN_ISOLATION,
(SQLPOINTER)(a_ptrint)isolation,
SQL_IS_UINTEGER );
_c( conn->info->env, conn->dbc, NULL );
ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLExecDirect( stmt, (SQLCHAR *)drop, SQL_NTS );
ret = SQLExecDirect( stmt, (SQLCHAR *)create, SQL_NTS );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLExecDirect( stmt, (SQLCHAR *)insert, SQL_NTS );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt );
_c( conn->info->env, conn->dbc, stmt );
printf( "table is created with %s\n", create );
printf( "I am sleeping ...\n" );
Sleep( 20000 );
printf( "I am rolling back the tran\n" );
ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK );
done:
return;
}
#else
void ShowBug( p_odbc_conn conn )
/******************************/
{
SQLHSTMT stmt;
RETCODE ret;
char * select = "select c1, c2 from test";
SQLINTEGER c1;
SQLINTEGER c2;
SQLINTEGER c1_ind;
SQLINTEGER c2_ind;
SQLINTEGER isolation = SQL_TXN_READ_COMMITTED;
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_AUTOCOMMIT,
(SQLPOINTER)SQL_AUTOCOMMIT_OFF,
SQL_IS_UINTEGER );
_c( conn->info->env, conn->dbc, NULL );
ret = SQLSetConnectAttr( conn->dbc,
SQL_ATTR_TXN_ISOLATION,
(SQLPOINTER)(a_ptrint)isolation,
SQL_IS_UINTEGER );
_c( conn->info->env, conn->dbc, NULL );
ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLPrepare( stmt, (SQLCHAR *)select, SQL_NTS );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLBindCol( stmt, 1, SQL_C_SLONG, &c1, sizeof( c1 ), &c1_ind );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLBindCol( stmt, 2, SQL_C_SLONG, &c2, sizeof( c2 ), &c2_ind );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLExecute( stmt );
_c( conn->info->env, conn->dbc, stmt );
while( ( ret = SQLFetch( stmt ) ) != SQL_NO_DATA ) {
printf( "ret = %d c1 = %d, c1_ind = %d, c2 = %d, c2_ind = %d\n",
ret, c1, c1_ind, c2, c2_ind );
}
ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt );
_c( conn->info->env, conn->dbc, stmt );
ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK );
done:
return;
}
#endif
int main( int argc, char *argv[] )
/********************************/
{
p_odbc_info info = NULL;
p_odbc_conn conn = NULL;
info = Init();
if( info != NULL ) {
argc = argc; // Unused
conn = Connect( info, argv[ 1 ] );
if( conn != NULL ) {
// ===========================
ShowBug( conn );
// ===========================
Disconnect( conn );
}
Fini( info );
}
return( 0 );
}
------------------------------------------------------------------
Description: It seems there is a bug in the MySQL ODBC driver 03.51.20 with the MySQL Server 5.1.22. This MySQL ODBC driver or the server allows dirty reading even after the isolation level is set to SQL_TXN_READ_COMMITTED with the following ODBC API SQLINTEGER isolation = SQL_TXN_READ_COMMITTED; ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)(a_ptrint)isolation, SQL_IS_UINTEGER ); I have two apps: app 1 issues inserts to a table named test (without commit) and then goes to sleep and app 2 fetches rows from the test table when the first app is sleeping. I can see app 2 will fetch all the rows inserted by app 1, even app 1 did not commit the transaction. This problem still happens even my table is created with the clause, "engine=InnoDB". Please note: the driver and server work well if my ODBC app uses the default isolation level, I believe that is SQL_TXN_REPEATABLE_READ with the MySQL ODBC driver 3.51.20 Here is my source code for app 1: void ShowBug( p_ml_host_conn conn ) /*********************************/ { SQLHSTMT stmt; RETCODE ret; char * drop = "drop table test"; char * create = "create table test( c1 int primary key, c2 int ) engine InnoDB"; char * insert = "insert into test values( 1, 1 )"; SQLINTEGER isolation = SQL_TXN_READ_COMMITTED; ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_AUTOCOMMIT, (SQLPOINTER)SQL_AUTOCOMMIT_OFF, SQL_IS_UINTEGER ); _c( conn->host->env, conn->dbc, NULL ); ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)(a_ptrint)isolation, SQL_IS_UINTEGER ); _c( conn->host->env, conn->dbc, NULL ); ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLExecDirect( stmt, (SQLCHAR *)drop, SQL_NTS ); ret = SQLExecDirect( stmt, (SQLCHAR *)create, SQL_NTS ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLExecDirect( stmt, (SQLCHAR *)insert, SQL_NTS ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt ); _c( conn->host->env, conn->dbc, stmt ); printf( "I am sleeping ...\n" ); Sleep( 20000 ); printf( "I am rolling back the tran\n" ); ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK ); done: return; } and the source code for app 2: void ShowBug( p_ml_host_conn conn ) /*********************************/ { SQLHSTMT stmt; RETCODE ret; char * select = "select c1, c2 from test"; SQLINTEGER c1; SQLINTEGER c2; SQLINTEGER c1_ind; SQLINTEGER c2_ind; SQLINTEGER isolation = SQL_TXN_READ_COMMITTED; ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_AUTOCOMMIT, (SQLPOINTER)SQL_AUTOCOMMIT_OFF, SQL_IS_UINTEGER ); _c( conn->host->env, conn->dbc, NULL ); ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)(a_ptrint)isolation, SQL_IS_UINTEGER ); _c( conn->host->env, conn->dbc, NULL ); ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLPrepare( stmt, (SQLCHAR *)select, SQL_NTS ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLBindCol( stmt, 1, SQL_C_SLONG, &c1, sizeof( c1 ), &c1_ind ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLBindCol( stmt, 2, SQL_C_SLONG, &c2, sizeof( c2 ), &c2_ind ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLExecute( stmt ); _c( conn->host->env, conn->dbc, stmt ); while( ( ret = SQLFetch( stmt ) ) != SQL_NO_DATA ) { printf( "ret = %d c1 = %d, c1_ind = %d, c2 = %d, c2_ind = %d\n", ret, c1, c1_ind, c2, c2_ind ); } ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt ); _c( conn->host->env, conn->dbc, stmt ); ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK ); done: return; } How to repeat: Build two applications with the attached source code: compile one with -DINSERT and the second one without this flag. Then run app 1 and app2 consecutively and then you'll see app 2 will show the un-committed insert. The command line to start app1 or app2 could be odbcbug.exe "dsn=mydsn;uid=myuid;pwd=mypassword" Here is the source code: ---------------------------------------------------------------------- // ODBCBugs.C - Simple ODBC skeleton for duplicating ODBC bugs // that can't be duplicated using ODBC Test. // The function called ShowBug() duplicates the problem. // To run the test, the first parameter must be an ODBC connection string // in quotes: // // odbcbug "dsn=mydsn;uid=myuid;pwd=mypwd" // #include <stdio.h> #include <stdlib.h> #include <string.h> #include <windows.h> #include <process.h> #include "odbc.h" #if ODBCVER < 0x0350 #error "***** This module requires ODBC 3.5 or higher *****" #endif typedef unsigned int uint32; typedef uint32 _W64 a_ptrint; typedef struct an_odbc_info { SQLHENV env; } an_odbc_info, *p_odbc_info; typedef struct an_odbc_conn { p_odbc_info info; SQLHDBC dbc; int kill; int done; } an_odbc_conn, *p_odbc_conn; #define _c( e, d, s ) \ if( ret != 0 && ret != SQL_SUCCESS_WITH_INFO ) { \ printf( "error at line: %d\n", __LINE__ ); \ ODBC_error( e, d, s ); \ goto done; \ } void ODBC_error( HENV henv, HDBC hdbc, HSTMT hstmt ) /**************************************************/ { UCHAR sqlstate[10]; UCHAR errmsg[SQL_MAX_MESSAGE_LENGTH]; SDWORD nativeerr; SWORD actualmsglen; RETCODE rc; loop: rc = SQLError( (SQLHENV)henv, (SQLHDBC)hdbc, (SQLHSTMT)hstmt, sqlstate, &nativeerr, errmsg, SQL_MAX_MESSAGE_LENGTH - 1, &actualmsglen ); if( rc == SQL_ERROR) { printf( "SQLError failed!\n"); return; } if( rc != SQL_NO_DATA_FOUND ) { printf( "SQLSTATE = %s\n", sqlstate ); printf( "NATIVE ERROR = %d\n", nativeerr ); errmsg[actualmsglen] = '\0'; printf( "MSG = %s\n\n", errmsg ); goto loop; } } p_odbc_info Init( void ) /**********************/ { p_odbc_info info; RETCODE ret; info = (p_odbc_info) malloc( sizeof( *info ) ); if( info != NULL ) { ret = SQLAllocHandle( SQL_HANDLE_ENV, SQL_NULL_HANDLE, &info->env ); _c( info->env, NULL, NULL ); ret = SQLSetEnvAttr( info->env, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0 ); _c( info->env, NULL, NULL ); } done: return( info ); } void Fini( p_odbc_info info ) /***************************/ { RETCODE ret; // Clean up any resources and shut the module down. if( info->env != SQL_NULL_HENV ) { ret = SQLFreeHandle( SQL_HANDLE_ENV, info->env ); } } p_odbc_conn Connect( /******************/ p_odbc_info info, char * conn_str ) { // Establish a connection with the host database. This may // create a new connection or just grab one from a pool // of connections. p_odbc_conn conn; SQLSMALLINT conn_str_len; char out_str[ 2048 ]; RETCODE ret = SQL_ERROR; conn = (p_odbc_conn) malloc( sizeof( an_odbc_conn ) ); if( conn == NULL ) { goto done; } conn->info = info; conn->dbc = SQL_NULL_HDBC; conn->done = FALSE; ret = SQLAllocHandle( SQL_HANDLE_DBC, info->env, &conn->dbc ); _c( info->env, conn->dbc, NULL ); ret = SQLDriverConnect( conn->dbc, NULL, // HWND_NULL, (SQLCHAR *)conn_str, SQL_NTS, (SQLCHAR *)out_str, sizeof( out_str ), &conn_str_len, SQL_DRIVER_NOPROMPT ); _c( info->env, conn->dbc, NULL ); if( ( ret != SQL_SUCCESS ) && ( ret != SQL_SUCCESS_WITH_INFO ) ) { conn = NULL; goto done; } // Use transactions instead of auto-commit ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_AUTOCOMMIT, (SQLPOINTER)SQL_AUTOCOMMIT_OFF, SQL_IS_UINTEGER ); _c( info->env, conn->dbc, NULL ); done: return( conn ); } void Disconnect( p_odbc_conn conn ) /*********************************/ { if( conn != NULL ) { if( conn->dbc != SQL_NULL_HDBC ) { SQLDisconnect( conn->dbc ); SQLFreeHandle( SQL_HANDLE_DBC, conn->dbc ); } free( conn ); } } #ifdef INSERT void ShowBug( p_odbc_conn conn ) /******************************/ { SQLHSTMT stmt; RETCODE ret; char * drop = "drop table test"; char * create = "create table test( c1 int primary key, c2 int ) engine=InnoDB"; char * insert = "insert into test values( 1, 1 )"; SQLINTEGER isolation = SQL_TXN_READ_COMMITTED; ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_AUTOCOMMIT, (SQLPOINTER)SQL_AUTOCOMMIT_OFF, SQL_IS_UINTEGER ); _c( conn->info->env, conn->dbc, NULL ); ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)(a_ptrint)isolation, SQL_IS_UINTEGER ); _c( conn->info->env, conn->dbc, NULL ); ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLExecDirect( stmt, (SQLCHAR *)drop, SQL_NTS ); ret = SQLExecDirect( stmt, (SQLCHAR *)create, SQL_NTS ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLExecDirect( stmt, (SQLCHAR *)insert, SQL_NTS ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt ); _c( conn->info->env, conn->dbc, stmt ); printf( "table is created with %s\n", create ); printf( "I am sleeping ...\n" ); Sleep( 20000 ); printf( "I am rolling back the tran\n" ); ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK ); done: return; } #else void ShowBug( p_odbc_conn conn ) /******************************/ { SQLHSTMT stmt; RETCODE ret; char * select = "select c1, c2 from test"; SQLINTEGER c1; SQLINTEGER c2; SQLINTEGER c1_ind; SQLINTEGER c2_ind; SQLINTEGER isolation = SQL_TXN_READ_COMMITTED; ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_AUTOCOMMIT, (SQLPOINTER)SQL_AUTOCOMMIT_OFF, SQL_IS_UINTEGER ); _c( conn->info->env, conn->dbc, NULL ); ret = SQLSetConnectAttr( conn->dbc, SQL_ATTR_TXN_ISOLATION, (SQLPOINTER)(a_ptrint)isolation, SQL_IS_UINTEGER ); _c( conn->info->env, conn->dbc, NULL ); ret = SQLAllocHandle( SQL_HANDLE_STMT, conn->dbc, &stmt ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLPrepare( stmt, (SQLCHAR *)select, SQL_NTS ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLBindCol( stmt, 1, SQL_C_SLONG, &c1, sizeof( c1 ), &c1_ind ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLBindCol( stmt, 2, SQL_C_SLONG, &c2, sizeof( c2 ), &c2_ind ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLExecute( stmt ); _c( conn->info->env, conn->dbc, stmt ); while( ( ret = SQLFetch( stmt ) ) != SQL_NO_DATA ) { printf( "ret = %d c1 = %d, c1_ind = %d, c2 = %d, c2_ind = %d\n", ret, c1, c1_ind, c2, c2_ind ); } ret = SQLFreeHandle( SQL_HANDLE_STMT, stmt ); _c( conn->info->env, conn->dbc, stmt ); ret = SQLEndTran( SQL_HANDLE_DBC, conn->dbc, SQL_ROLLBACK ); done: return; } #endif int main( int argc, char *argv[] ) /********************************/ { p_odbc_info info = NULL; p_odbc_conn conn = NULL; info = Init(); if( info != NULL ) { argc = argc; // Unused conn = Connect( info, argv[ 1 ] ); if( conn != NULL ) { // =========================== ShowBug( conn ); // =========================== Disconnect( conn ); } Fini( info ); } return( 0 ); } ------------------------------------------------------------------