MDEV-9083: Slave IO thread does not handle autoreconnect to restarting Galera Cluster node

Chery-picked commits from codership/mysql-wsrep.

MW-284: Slave I/O retry on ER_COM_UNKNOWN_ERROR

Slave would treat ER_COM_UNKNOWN_ERROR as fatal error and stop.
The fix here is to treat it as a network error and rely on the
built-in mechanism to retry.

MW-284: Add an MTR test

mysql-test/suite/galera/r/MW-284.result

+CREATE TABLE t1 (f1 INTEGER) ENGINE=InnoDB;
+SET GLOBAL wsrep_provider_options='gmcast.isolate=1';
+SET SESSION wsrep_on = OFF;
+SET SESSION wsrep_on = ON;
+START SLAVE;
+include/wait_for_slave_param.inc [Slave_IO_Running]
+SET GLOBAL wsrep_provider_options='gmcast.isolate=0';
+include/wait_for_slave_to_start.inc
+INSERT INTO t1 VALUES (1);
+DROP TABLE t1;
+STOP SLAVE;
+RESET SLAVE ALL;
+CALL mtr.add_suppression('failed registering on master');

mysql-test/suite/galera/t/MW-284.cnf

+!include ../galera_2nodes_as_master.cnf

mysql-test/suite/galera/t/MW-284.test

+#
+# MW-284 Slave I/O retry on ER_COM_UNKNOWN_ERROR
+#
+
+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+
+--connect node_3, 127.0.0.1, root, , test, $NODE_MYPORT_3
+--disable_query_log
+--eval CHANGE MASTER TO MASTER_HOST='127.0.0.1', MASTER_PORT=$NODE_MYPORT_1, MASTER_USER='root', MASTER_CONNECT_RETRY=1;
+--enable_query_log
+
+--connection node_1
+CREATE TABLE t1 (f1 INTEGER) ENGINE=InnoDB;
+SET GLOBAL wsrep_provider_options='gmcast.isolate=1';
+SET SESSION wsrep_on = OFF;
+--let $wait_condition = SELECT VARIABLE_VALUE = 'non-Primary' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_status'
+--source include/wait_condition.inc
+SET SESSION wsrep_on = ON;
+
+--connection node_3
+START SLAVE;
+--sleep 1
+--let $slave_param= Slave_IO_Running
+--let $slave_param_value= Connecting
+--source include/wait_for_slave_param.inc
+
+--connection node_1
+SET GLOBAL wsrep_provider_options='gmcast.isolate=0';
+
+# We expect the slave to reconnect and resume replication
+
+--connection node_3
+--source include/wait_for_slave_to_start.inc
+
+--connection node_1
+INSERT INTO t1 VALUES (1);
+
+--connection node_3
+--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 't1'
+--source include/wait_condition.inc
+--let $wait_condition = SELECT COUNT(*) > 0 FROM t1
+--source include/wait_condition.inc
+
+# Cleanup
+
+--connection node_1
+DROP TABLE t1;
+
+--connection node_3
+--let $wait_condition = SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 't1'
+--source include/wait_condition.inc
+
+STOP SLAVE;
+RESET SLAVE ALL;
+
+CALL mtr.add_suppression('failed registering on master');

sql/slave.cc

@@ -1361,6 +1361,10 @@ bool is_network_error(uint errorno)
       errorno == ER_NET_READ_INTERRUPTED ||
       errorno == ER_SERVER_SHUTDOWN)
     return TRUE;
+#ifdef WITH_WSREP
+  if (errorno == ER_UNKNOWN_COM_ERROR)
+    return TRUE;
+#endif
 
   return FALSE;   
 }