I've implemented ODBC reconnect when connection not open or
communication link failure.
Modifications of source
1. my_con.h
1.1. add defines
#define CON_ID(db_con) (((struct my_con*)((db_con)->tail))->id)
#define CON_ENV(db_con) (((struct my_con*)((db_con)->tail))->env)
#define MAX_CONN_STR_LEN 2048
1.2. add declaration of function build_conn_str
char *build_conn_str(struct db_id* id, char *buf);
2. my_con.c
2.1 remove define MAX_CONN_STR_LEN which we moved to my_con.h
#define MAX_CONN_STR_LEN 2048
2.2. modify build_conn_str function
the buf which is saved the connect string is the parameter
the beginning of the function is
============
char *build_conn_str(struct db_id* id, char *buf)
{
int len, ld, lu, lp;
char *p;
if (!buf) return 0;
ld = id->database?strlen(id->database):0;
============
2.3. modify new_connection function
2.3.1 change definition of conn_str
========
char conn_str[MAX_CONN_STR_LEN];
========
2.3.2 change call of the function build_conn_str to
========
if (!build_conn_str(id, conn_str)) {
========
3. file dbase.c function submit_query
3.1. add some local variables
========
SQLCHAR outstr[1024];
SQLSMALLINT outstrlen;
SQLCHAR sqlstate[15];
SQLCHAR ErrorMsg[SQL_MAX_MESSAGE_LENGTH+1];
SQLINTEGER native_error = 0;
char conn_str[MAX_CONN_STR_LEN];
SQLRETURN sts;
========
3.2. and check slqstate of SQLAllocStmt and try to reconnect if
connection not open or communication link failure.
new code
========
ret = SQLAllocStmt(CON_CONNECTION(_h), &CON_RESULT(_h));
if (!SQL_SUCCEEDED(ret))
{
LOG(L_ERR, "ERROR:unixodbc:submit_query: Statement allocation error
%d\n",
(int)(long)CON_CONNECTION(_h));
extract_error("SQLAllocStmt", CON_CONNECTION(_h), SQL_HANDLE_DBC);
sts = SQLError (CON_ENV(_h), CON_CONNECTION(_h), SQL_NULL_HSTMT,
sqlstate, &native_error,
ErrorMsg, sizeof(ErrorMsg), NULL);
if (SQL_SUCCEEDED (sts) &&
strncmp(sqlstate,"08003",5)!=0 && /* Connect not open */
strncmp(sqlstate,"08S01",5)!=0) /* Communication link failure */ {
return ret;
}
LOG(L_ERR, "ERROR:unixodbc:submit_query: try to
reconnect\n");
// Disconnect
SQLDisconnect (CON_CONNECTION(_h));
// Reconnect
if (!build_conn_str(CON_ID(_h), conn_str)) {
LOG(L_ERR, "ERROR:unixodbc:submit_query: failed to
build connection string\n");
return ret;
}
ret = SQLDriverConnect(CON_CONNECTION(_h), (void *)1,
(SQLCHAR*)conn_str,
SQL_NTS, outstr, sizeof(outstr), &outstrlen,
SQL_DRIVER_COMPLETE);
if (!SQL_SUCCEEDED(ret)) {
LOG(L_ERR, "ERROR:unixodbc:submit_query: failed to
connect\n");
extract_error("SQLDriverConnect", CON_CONNECTION(_h),
SQL_HANDLE_DBC);
return ret;
}
ret = SQLAllocStmt(CON_CONNECTION(_h), &CON_RESULT(_h));
if (!SQL_SUCCEEDED(ret))
{
LOG(L_ERR, "Statement allocation error %d\n",
(int)(long)CON_CONNECTION(_h));
extract_error("SQLAllocStmt", CON_CONNECTION(_h), SQL_HANDLE_DBC);
return ret;
}
}
========
Best regards,
Alex Gradinar
----- Original Message ----- From: "Alex Gradinar"
<[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, February 28, 2006 5:13 PM
Subject: unixodbc bugs
1. function convert_rows in file res.c
while allocationg memery to columns of row in this code
==========
CON_ROW(_h) = (strn*)pkg_malloc((int)columns);
==========
allocate only amount of bytes as number of columns,
but we have to allocate number of columns * sizeof struct strn
This is correct code
==========
CON_ROW(_h) = (strn*)pkg_malloc((int)columns*sizeof(strn));
==========
2. function convert_rows in file res.c
while getting data from odbc in this code
==========
ret = SQLGetData(CON_RESULT(_h), i, SQL_C_CHAR,
(CON_ROW(_h)[i-1]).s, 1024, &indicator);
==========
write 1024 bytes, but if we chage size of variable 's' in struct strn
we have to keep in mind that this number of bytes we have to change too.
This is correct code
==========
ret = SQLGetData(CON_RESULT(_h), i, SQL_C_CHAR,
(CON_ROW(_h)[i-1]).s, sizeof((CON_ROW(_h)[i-1]).s), &indicator);
==========
3. function submit_query in dbase.c
in this code
==========
if(CON_RESULT(_h))
{
ret = SQLFreeStmt(&CON_RESULT(_h), SQL_CLOSE);
if (!SQL_SUCCEEDED(ret))
{
LOG(L_ERR, "Statement allocation error %d\n",
(int)(long)CON_CONNECTION(_h));
extract_error("SQLAllocStmt",
CON_CONNECTION(_h), SQL_HANDLE_DBC);
return ret;
}
}
==========
3.1. call the function SQLFreeStmt, but error about allocation
3.2. with my odbc driver (OpenLink) SQLFreeStmt returned Error
I recomend to change this code to
==========
if(CON_RESULT(_h))
{
SQLFreeStmt(&CON_RESULT(_h), SQL_RESET_PARAMS);
SQLFreeStmt(&CON_RESULT(_h), SQL_UNBIND);
SQLFreeStmt(&CON_RESULT(_h), SQL_CLOSE);
SQLFreeStmt(&CON_RESULT(_h), SQL_DROP)
}
==========
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