Bug #12573 C api function mysql_next_result() and mysql_more_results() return error

• Submitted: 14 Aug 2005 13:20
• Modified: 24 Aug 2005 9:05
• Reporter: sanxi wang
• Status: Not a Bug
• Category: MySQL Server
• Severity: S3 (Non-critical)
• Version: 5.0.10-0
• OS: Linux (Redhat Linux 9)
• Assigned to: Georg Richter
• CPU Architecture: Any

[14 Aug 2005 13:20] sanxi wang

Description:
version: 
  client: MySQL-client-5.0.10-0
           MySQL-devel-5.0.10-0
  server: MySQL-server-5.0.10-0

When no more data, mysql_next_result() still return 0

How to repeat:
use C API call stored procedure and use mysql_next_result get last result:

call stored procedure like:
CREATE PROCEDURE `test`()
    NOT DETERMINISTIC
    SQL SECURITY DEFINER
    COMMENT ''
BEGIN
    select 1;
    select 2;
    select 3;
end;

then use C API the get result:
...
mysql_init(&mysql);
mysql_real_connect(&mysql, hostname, username, passwd, dbname, 0, NULL, CLIENT_MULTI_RESULTS);
...
mysql_ping(&mysql);
mysql_real_query(&mysql, access, (unsigned int) strlen(access));

       do
        {
        // Process all results
                if (!(res= mysql_store_result(&mysql))) return -5;

                if(row = mysql_fetch_row(res))
                {
                        if( mysql_num_fields(res)  >=  4 )
                        {
                                if(row[0]!=NULL)
                                        strncpy(buff01, row[0], 1023);          // save the data
                        }
                }

                mysql_free_result(res);

// FOR BUG OF MySQL C API:
// If no more data, must call mysql_next_result on 2 times
// At the next time, my_sql_next_result will return -1 and mysql_more_results will return 0;
// Otherwise, mysql_next_result will return 0(success)
                mysql_next_result(&mysql); mysql_more_results(&mysql);
        } while (mysql_next_result(&mysql)!=-1);

[24 Aug 2005 9:05] Georg Richter

When calling a stored procedure you have an additional (empty) resultset and errorcode for the procedure call itself. Same behaviour when you mix select and dml statements in a multi query. For statements which don't return a resultset (like INSERT/DELETE/UPDATE) you will get only the errorcode.