Detect manual commands faster

Previous, MariaDBMonitor would wait until the next monitor interval before detecting
a new manual command. The commands are now checked every 100 ms.

include/maxscale/monitor.hh

@@ -209,6 +209,15 @@ protected:
      */
     virtual void process_state_changes();
 
+    /**
+     * Should a monitor tick be ran immediately? The base class version always returns false. A monitor can
+     * override this to add specific conditions. This function is called every MXS_MON_BASE_INTERVAL_MS
+     * (100 ms) by the monitor worker thread, which then runs a monitor tick if true is returned.
+     *
+     * @return True if tick should be ran
+     */
+    virtual bool immediate_tick_required() const;
+
     MXS_MONITOR*          m_monitor;    /**< The generic monitor structure. */
     MXS_MONITORED_SERVER* m_master;     /**< Master server */
 

server/core/monitor.cc

@@ -2496,7 +2496,7 @@ MonitorInstance::MonitorInstance(MXS_MONITOR* pMonitor)
     , m_thread_running(false)
     , m_shutdown(0)
     , m_checked(false)
-    , m_loop_called(0)
+    , m_loop_called(get_time_ms())
 {
 }
 
@@ -2563,8 +2563,7 @@ bool MonitorInstance::start(const MXS_CONFIG_PARAMETER* pParams)
 
         if (configure(pParams))
         {
-            m_loop_called = 0;
-
+            m_loop_called = get_time_ms() - m_monitor->interval; // Next tick should happen immediately.
             if (!Worker::start())
             {
                 MXS_ERROR("Failed to start worker for monitor '%s'.", m_monitor->name);
@@ -2906,14 +2905,15 @@ bool MonitorInstance::call_run_one_tick(Worker::Call::action_t action)
     if (action == Worker::Call::EXECUTE)
     {
         int64_t now = get_time_ms();
-
+        // Enough time has passed,
         if ((now - m_loop_called > static_cast<int64_t>(m_monitor->interval))
-            || atomic_load_int(&m_monitor->check_maintenance_flag) == MAINTENANCE_FLAG_CHECK)
+            // or maintenance flag is set,
+            || atomic_load_int(&m_monitor->check_maintenance_flag) == MAINTENANCE_FLAG_CHECK
+            // or a monitor-specific condition is met.
+            || immediate_tick_required())
         {
             m_loop_called = now;
-
             run_one_tick();
-
             now = get_time_ms();
         }
 
@@ -2925,7 +2925,6 @@ bool MonitorInstance::call_run_one_tick(Worker::Call::action_t action)
 
         delayed_call(delay, &MonitorInstance::call_run_one_tick, this);
     }
-
     return false;
 }
 
@@ -2943,4 +2942,9 @@ void MonitorInstance::run_one_tick()
     mon_hangup_failed_servers(m_monitor);
     store_server_journal(m_monitor, m_master);
 }
+
+bool MonitorInstance::immediate_tick_required() const
+{
+    return false;
+}
 }

server/modules/monitor/mariadbmon/mariadbmon.cc

@@ -757,6 +757,11 @@ bool MariaDBMonitor::execute_manual_command(std::function<void(void)> command, j
     return rval;
 }
 
+bool MariaDBMonitor::immediate_tick_required() const
+{
+    return m_manual_cmd.command_waiting_exec;
+}
+
 bool MariaDBMonitor::run_manual_switchover(SERVER* promotion_server, SERVER* demotion_server,
                                            json_t** error_out)
 {

server/modules/monitor/mariadbmon/mariadbmon.hh

@@ -245,6 +245,7 @@ private:
     void clear_server_info();
     void reset_node_index_info();
     bool execute_manual_command(std::function<void ()> command, json_t** error_out);
+    bool immediate_tick_required() const;
 
     std::string diagnostics_to_string() const;
     json_t*     to_json() const;