MDEV-21479 : Galera 4 unable to query cluster state if not primary co…

…mponent

Set mysql.wsrep_cluster and mysql.wsrep_cluster_members as
TABLE_CATEGORY_INFORMATION as mysql.wsrep_streaming_log
so that they can be queried even if node is not primary
component.

Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

mysql-test/suite/galera/r/MDEV-21479.result

@@ -0,0 +1,95 @@
+connection node_2;
+connection node_1;
+# Lets first see that we can access wsrep schema tables
+# Node1
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+EXPECT_0
+0
+SELECT COUNT(*) AS EXPECT_1 from mysql.wsrep_cluster;
+EXPECT_1
+1
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+EXPECT_2
+2
+connection node_2;
+# Node2
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+EXPECT_0
+0
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+EXPECT_1
+1
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+EXPECT_2
+2
+connection node_1;
+SET GLOBAL wsrep_provider_options = 'pc.ignore_sb=true';
+SET GLOBAL wsrep_provider_options = 'pc.weight=2';
+connection node_2;
+# Desync and disconnect node_2
+SET @@global.wsrep_desync = 1;
+SET SESSION wsrep_dirty_reads=1;
+SET SESSION wsrep_sync_wait=0;
+SET GLOBAL wsrep_provider_options = 'gmcast.isolate=1';
+SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_status';
+VARIABLE_VALUE
+non-Primary
+connection node_1;
+# Waiting until node_2 is not part of cluster anymore
+# Verify that we can access wsrep schema tables
+# Node1
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+EXPECT_0
+0
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+EXPECT_1
+1
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster_members;
+EXPECT_1
+1
+connection node_2;
+# Node2
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+EXPECT_0
+0
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+EXPECT_1
+1
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+EXPECT_2
+2
+connection node_2;
+# Reconnect node_2 back to cluster
+SET GLOBAL wsrep_provider_options = 'gmcast.isolate=0';
+SET wsrep_dirty_reads=0;
+SHOW STATUS LIKE 'wsrep_desync_count';
+Variable_name	Value
+wsrep_desync_count	0
+SET @@global.wsrep_desync = 0;
+CALL mtr.add_suppression("WSREP: Protocol violation. JOIN message sender (.*) is not in state transfer \\(SYNCED\\). Message ignored.");
+connection node_1;
+# Wait until both nodes are back to cluster
+SET GLOBAL wsrep_provider_options = 'pc.ignore_sb=false';
+SET GLOBAL wsrep_provider_options = 'pc.weight=1';
+# Verify that we can access wsrep schema tables
+# Node1
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+EXPECT_0
+0
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+EXPECT_1
+1
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+EXPECT_2
+2
+connection node_2;
+# Node2
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+EXPECT_0
+0
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+EXPECT_1
+1
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+EXPECT_2
+2

mysql-test/suite/galera/t/MDEV-21479.test

@@ -0,0 +1,99 @@
+#
+# MDEV-21479 : Galera 4 unable to query cluster state if not primary component
+#
+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+
+
+--echo # Lets first see that we can access wsrep schema tables
+--echo # Node1
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+SELECT COUNT(*) AS EXPECT_1 from mysql.wsrep_cluster;
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+
+--connection node_2
+--echo # Node2
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+
+--connection node_1
+# Make node 1 tolerate split-brain
+SET GLOBAL wsrep_provider_options = 'pc.ignore_sb=true';
+SET GLOBAL wsrep_provider_options = 'pc.weight=2';
+
+# Desync and disconnect node 2 from the PC:
+--connection node_2
+--echo # Desync and disconnect node_2
+SET @@global.wsrep_desync = 1;
+SET SESSION wsrep_dirty_reads=1;
+SET SESSION wsrep_sync_wait=0;
+SET GLOBAL wsrep_provider_options = 'gmcast.isolate=1';
+--let $wait_condition = SELECT VARIABLE_VALUE = 'non-Primary' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_status';
+--source include/wait_condition.inc
+SELECT VARIABLE_VALUE FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_status';
+
+# Wait until node 2 disappears from the PC:
+--connection node_1
+--echo # Waiting until node_2 is not part of cluster anymore
+--let $wait_condition = SELECT VARIABLE_VALUE = 1 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_size';
+--source include/wait_condition.inc
+--let $wait_condition = SELECT VARIABLE_VALUE = 'Primary' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_status';
+--source include/wait_condition.inc
+
+--echo # Verify that we can access wsrep schema tables
+--echo # Node1
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster_members;
+
+--connection node_2
+#
+# Here node2 remembers old configuration even when we are non-Primary
+#
+--echo # Node2
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+
+# Reconnect node 2 to the PC:
+--connection node_2
+--echo # Reconnect node_2 back to cluster
+SET GLOBAL wsrep_provider_options = 'gmcast.isolate=0';
+SET wsrep_dirty_reads=0;
+--let $wait_condition = SELECT VARIABLE_VALUE = 'Primary' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_status';
+--source include/wait_condition.inc
+--let $wait_condition = SELECT VARIABLE_VALUE = 2 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_size';
+--source include/wait_condition.inc
+--let $wait_condition = SELECT VARIABLE_VALUE = 'ON' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_ready';
+--source include/wait_condition.inc
+
+# Must return 0:
+SHOW STATUS LIKE 'wsrep_desync_count';
+
+# Resync node_2, should pass:
+SET @@global.wsrep_desync = 0;
+
+--let $wait_condition = SELECT VARIABLE_VALUE = 'Synced' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_local_state_comment';
+--source include/wait_condition.inc
+
+CALL mtr.add_suppression("WSREP: Protocol violation. JOIN message sender (.*) is not in state transfer \\(SYNCED\\). Message ignored.");
+
+--connection node_1
+--echo # Wait until both nodes are back to cluster
+--let $wait_condition = SELECT VARIABLE_VALUE = 2 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_cluster_size';
+--source include/wait_condition.inc
+SET GLOBAL wsrep_provider_options = 'pc.ignore_sb=false';
+SET GLOBAL wsrep_provider_options = 'pc.weight=1';
+
+--echo # Verify that we can access wsrep schema tables
+--echo # Node1
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;
+
+--connection node_2
+--echo # Node2
+SELECT COUNT(*) AS EXPECT_0 FROM mysql.wsrep_streaming_log;
+SELECT COUNT(*) AS EXPECT_1 FROM mysql.wsrep_cluster;
+SELECT COUNT(*) AS EXPECT_2 FROM mysql.wsrep_cluster_members;

sql/table.cc

@@ -45,6 +45,9 @@
 #include "ha_sequence.h"
 #include "sql_show.h"
 #include "opt_trace.h"
+#ifdef WITH_WSREP
+#include "wsrep_schema.h"
+#endif
 
 /* For MySQL 5.7 virtual fields */
 #define MYSQL57_GENERATED_FIELD 128
@@ -264,10 +267,14 @@ TABLE_CATEGORY get_table_category(const LEX_CSTRING *db,
   DBUG_ASSERT(name != NULL);
 
 #ifdef WITH_WSREP
-  if (my_strcasecmp(system_charset_info, db->str, "mysql") == 0 &&
-      my_strcasecmp(system_charset_info, name->str, "wsrep_streaming_log") == 0)
+  if (my_strcasecmp(system_charset_info, db->str, WSREP_SCHEMA) == 0)
   {
-    return TABLE_CATEGORY_INFORMATION;
+    if ((my_strcasecmp(system_charset_info, name->str, WSREP_STREAMING_TABLE) == 0 ||
+         my_strcasecmp(system_charset_info, name->str, WSREP_CLUSTER_TABLE) == 0 ||
+         my_strcasecmp(system_charset_info, name->str, WSREP_MEMBERS_TABLE) == 0))
+    {
+      return TABLE_CATEGORY_INFORMATION;
+    }
   }
 #endif /* WITH_WSREP */
   if (is_infoschema_db(db))

sql/wsrep_schema.cc

@@ -35,11 +35,6 @@
 #include <string>
 #include <sstream>
 
-#define WSREP_SCHEMA          "mysql"
-#define WSREP_STREAMING_TABLE "wsrep_streaming_log"
-#define WSREP_CLUSTER_TABLE   "wsrep_cluster"
-#define WSREP_MEMBERS_TABLE   "wsrep_cluster_members"
-
 const char* wsrep_sr_table_name_full= WSREP_SCHEMA "/" WSREP_STREAMING_TABLE;
 
 static const std::string wsrep_schema_str= WSREP_SCHEMA;

sql/wsrep_schema.h

@@ -33,6 +33,11 @@ struct TABLE_LIST;
 struct st_mysql_lex_string;
 typedef struct st_mysql_lex_string LEX_STRING;
 
+#define WSREP_SCHEMA          "mysql"
+#define WSREP_STREAMING_TABLE "wsrep_streaming_log"
+#define WSREP_CLUSTER_TABLE   "wsrep_cluster"
+#define WSREP_MEMBERS_TABLE   "wsrep_cluster_members"
+
 /** Name of the table in `wsrep_schema_str` used for storing streaming
 replication data. In an InnoDB full format, e.g. "database/tablename". */
 extern const char* wsrep_sr_table_name_full;