MXS-1156: Disable heartbeat if value is set to 0

MXS-1156: Disable heartbeat if value is set to 0.

A warning log is written in maxscale log file when heartbeat is not set.

server/modules/routing/binlogrouter/blr.c

@@ -647,7 +647,7 @@ createInstance(SERVICE *service, char **options)
                 {
                     int h_val = (int)strtol(value, NULL, 10);
 
-                    if (h_val <= 0 ||
+                    if (h_val < 0 ||
                         (errno == ERANGE) ||
                         h_val > BLR_HEARTBEAT_MAX_INTERVAL)
                     {
@@ -658,6 +658,13 @@ createInstance(SERVICE *service, char **options)
                     }
                     else
                     {
+                        if (h_val == 0)
+                        {
+                            MXS_WARNING("%s: %s",
+                                        inst->service->name,
+                                        "MASTER_HEARTBEAT_PERIOD has been set to 0 (disabled): "
+                                        "a master network inactivity will not be handled.");
+                        }
                         inst->heartbeat = h_val;
                     }
                 }
@@ -1570,8 +1577,9 @@ diagnostics(MXS_ROUTER *router, DCB *dcb)
 
     dcb_printf(dcb, "\tBinlog directory:                            %s\n",
                router_inst->binlogdir);
-    dcb_printf(dcb, "\tHeartbeat period (seconds):                  %lu\n",
+    dcb_printf(dcb, "\tHeartbeat period (seconds):                  %lu%s\n",
-               router_inst->heartbeat);
+               router_inst->heartbeat,
+               router_inst->heartbeat ? "" : "(disabled)");
     dcb_printf(dcb, "\tNumber of master connects:                   %d\n",
                router_inst->stats.n_masterstarts);
     dcb_printf(dcb, "\tNumber of delayed reconnects:                %d\n",

server/modules/routing/binlogrouter/blr_master.c

@@ -103,7 +103,7 @@ void blr_notify_all_slaves(ROUTER_INSTANCE *router);
 extern bool blr_notify_waiting_slave(ROUTER_SLAVE *slave);
 extern bool blr_save_mariadb_gtid(ROUTER_INSTANCE *inst);
 static void blr_register_serverid(ROUTER_INSTANCE *router, GWBUF *buf);
-static void blr_register_heartbeat(ROUTER_INSTANCE *router, GWBUF *buf);
+static bool blr_register_heartbeat(ROUTER_INSTANCE *router, GWBUF *buf);
 static void blr_register_setchecksum(ROUTER_INSTANCE *router, GWBUF *buf);
 static void blr_register_getchecksum(ROUTER_INSTANCE *router, GWBUF *buf);
 static void blr_register_handle_checksum(ROUTER_INSTANCE *router, GWBUF *buf);
@@ -2328,11 +2328,15 @@ void blr_notify_all_slaves(ROUTER_INSTANCE *router)
  * Handles previous reply from Master and sends
  * SET @master_heartbeat_period to master
  *
+ * The statement is sent only if router->heartbeat > 0
+ *
  * @param router    Current router instance
  * @param buf       GWBUF with server reply to previous
  *                  registration command
+ * @return          True if hearbeat request has been sent
+ *                  false otherwise (router->heartbeat = 0)
  */
-static void blr_register_heartbeat(ROUTER_INSTANCE *router, GWBUF *buf)
+static bool blr_register_heartbeat(ROUTER_INSTANCE *router, GWBUF *buf)
 {
     char query[BLRM_SET_HEARTBEAT_QUERY_LEN];
     char *val = blr_extract_column(buf, 2);
@@ -2359,6 +2363,9 @@ static void blr_register_heartbeat(ROUTER_INSTANCE *router, GWBUF *buf)
     }
     MXS_FREE(val);
 
+    /* Send Heartbeat request ony if router->heartbeat is set */
+    if (router->heartbeat > 0)
+    {
         // Prepare new registration message
         sprintf(query,
                 "SET @master_heartbeat_period = %lu000000000",
@@ -2366,6 +2373,9 @@ static void blr_register_heartbeat(ROUTER_INSTANCE *router, GWBUF *buf)
         blr_register_send_command(router, query, BLRM_HBPERIOD);
     }
 
+    return router->heartbeat != 0;
+}
+
 /**
  * Slave Protocol registration to Master:
  *
@@ -2378,11 +2388,18 @@ static void blr_register_heartbeat(ROUTER_INSTANCE *router, GWBUF *buf)
  */
 static void blr_register_setchecksum(ROUTER_INSTANCE *router, GWBUF *buf)
 {
-    // Response from master should be stored
+    /**
+     * Response from master (set heartbeat reply) should be stored
+     * only if router->heartbeat is set
+     */
+    if (router->heartbeat > 0)
+    {
         blr_register_cache_response(router,
                                     &router->saved_master.heartbeat,
                                     "heartbeat",
                                     buf);
+    }
+
     // New registration message
     blr_register_send_command(router,
                               "SET @master_binlog_checksum ="
@@ -2858,8 +2875,11 @@ static void blr_start_master_registration(ROUTER_INSTANCE *router, GWBUF *buf)
         router->retry_backoff = 1;
         break;
     case BLRM_SERVERID:
-        blr_register_heartbeat(router, buf);
+        // If set heartbeat is not being sent, next state is BLRM_HBPERIOD
+        if (blr_register_heartbeat(router, buf))
+        {
             break;
+        }
     case BLRM_HBPERIOD:
         blr_register_setchecksum(router, buf);
         break;
@@ -3146,6 +3166,8 @@ static void blr_start_master_registration(ROUTER_INSTANCE *router, GWBUF *buf)
         /**
          * Set heartbeat check task
          */
+        if (router->heartbeat > 0)
+        {
             snprintf(task_name,
                      BLRM_TASK_NAME_LEN,
                      "%s heartbeat",
@@ -3154,6 +3176,7 @@ static void blr_start_master_registration(ROUTER_INSTANCE *router, GWBUF *buf)
                        blr_check_last_master_event,
                        router,
                        router->heartbeat);
+        }
 
         break;
     }

server/modules/routing/binlogrouter/blr_slave.c

@@ -3949,7 +3949,7 @@ int blr_handle_change_master(ROUTER_INSTANCE* router,
     {
         int h_val = (int)strtol(master_heartbeat, NULL, 10);
 
-        if (h_val <= 0 ||
+        if (h_val < 0 ||
             (errno == ERANGE) ||
             h_val > BLR_HEARTBEAT_MAX_INTERVAL)
         {
@@ -3973,6 +3973,13 @@ int blr_handle_change_master(ROUTER_INSTANCE* router,
         }
         else
         {
+            if (h_val == 0)
+            {
+                MXS_WARNING("%s: %s",
+                            router->service->name,
+                           "MASTER_HEARTBEAT_PERIOD has been set to 0 (disabled): "
+                           "a master network inactivity will not be handled.");
+            }
             router->heartbeat = h_val;
         }
     }