[Devel] unixodbc reconnect
Alex Gradinar
Alex.Gradinar at cartel.md
Tue Mar 14 15:04:30 CET 2006
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" <Alex.Gradinar at cartel.md>
To: <devel at openser.org>
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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