Bug#16918: Aborted_clients > Connections.

The problem was that aborted_threads variable was updated
twice when a client connection had been aborted.

The fix is to refactor a code to have aborted_threads updated
only in one place.

sql/mysql_priv.h

@@ -726,7 +726,6 @@ pthread_handler_t handle_bootstrap(void *arg);
 void end_thread(THD *thd,bool put_in_cache);
 void flush_thread_cache();
 bool mysql_execute_command(THD *thd);
-bool do_command(THD *thd);
 bool dispatch_command(enum enum_server_command command, THD *thd,
 		      char* packet, uint packet_length);
 void log_slow_statement(THD *thd);

sql/sql_parse.cc

@@ -93,6 +93,8 @@ const char *xa_state_names[]={
   "NON-EXISTING", "ACTIVE", "IDLE", "PREPARED"
 };
 
+static bool do_command(THD *thd);
+
 #ifdef __WIN__
 static void  test_signal(int sig_ptr)
 {
@@ -1199,23 +1201,28 @@ pthread_handler_t handle_one_connection(void *arg)
     }
     if (thd->user_connect)
       decrease_user_connections(thd->user_connect);
+
+    if (thd->killed ||
+        net->vio && net->error && net->report_error)
+    {
+      statistic_increment(aborted_threads, &LOCK_status);
+    }
+
     if (net->error && net->vio != 0 && net->report_error)
     {
       if (!thd->killed && thd->variables.log_warnings > 1)
-	sql_print_warning(ER(ER_NEW_ABORTING_CONNECTION),
+      {
+        sql_print_warning(ER(ER_NEW_ABORTING_CONNECTION),
                           thd->thread_id,(thd->db ? thd->db : "unconnected"),
                           sctx->user ? sctx->user : "unauthenticated",
                           sctx->host_or_ip,
                           (net->last_errno ? ER(net->last_errno) :
                            ER(ER_UNKNOWN_ERROR)));
+      }
+
       net_send_error(thd, net->last_errno, NullS);
-      statistic_increment(aborted_threads,&LOCK_status);
     }
-    else if (thd->killed)
-    {
-      statistic_increment(aborted_threads,&LOCK_status);
-    }
-    
+
 end_thread:
     close_connection(thd, 0, 1);
     end_thread(thd,1);
@@ -1550,12 +1557,12 @@ bool do_command(THD *thd)
     DBUG_PRINT("info",("Got error %d reading command from socket %s",
 		       net->error,
 		       vio_description(net->vio)));
+
     /* Check if we can continue without closing the connection */
+
     if (net->error != 3)
-    {
-      statistic_increment(aborted_threads,&LOCK_status);
       DBUG_RETURN(TRUE);			// We have to close it.
-    }
+
     net_send_error(thd, net->last_errno, NullS);
     net->error= 0;
     DBUG_RETURN(FALSE);