refs MW-245 - merged wsrep_dirty_reads and wsrep_reject_queries from PXC

mysql-test/suite/galera/r/galera_defaults.result

 SELECT COUNT(*) = 43 FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'wsrep_%';
 COUNT(*) = 43
-1
+0
 SELECT VARIABLE_NAME, VARIABLE_VALUE
 FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
 WHERE VARIABLE_NAME LIKE 'wsrep_%'
@@ -40,6 +40,7 @@ WSREP_NOTIFY_CMD
 WSREP_ON	ON
 WSREP_OSU_METHOD	TOI
 WSREP_RECOVER	OFF
+WSREP_REJECT_QUERIES	NONE
 WSREP_REPLICATE_MYISAM	OFF
 WSREP_RESTART_SLAVE	OFF
 WSREP_RETRY_AUTOCOMMIT	1

mysql-test/suite/galera/r/galera_schema_dirty_reads.result

+USE information_schema;
+SELECT * FROM SESSION_VARIABLES WHERE VARIABLE_NAME LIKE "wsrep_dirty_reads";
+VARIABLE_NAME	VARIABLE_VALUE
+WSREP_DIRTY_READS	OFF
+SET GLOBAL wsrep_reject_queries=ALL;
+SELECT * FROM SESSION_VARIABLES WHERE VARIABLE_NAME LIKE "wsrep_dirty_reads";
+VARIABLE_NAME	VARIABLE_VALUE
+WSREP_DIRTY_READS	OFF
+SET GLOBAL wsrep_reject_queries=NONE;
+SET SESSION wsrep_dirty_reads=TRUE;
+SELECT * FROM SESSION_VARIABLES WHERE VARIABLE_NAME LIKE "wsrep_dirty_reads";
+VARIABLE_NAME	VARIABLE_VALUE
+WSREP_DIRTY_READS	ON

mysql-test/suite/galera/r/galera_var_cluster_address.result

 SET GLOBAL wsrep_cluster_address = 'foo://';
 SET SESSION wsrep_sync_wait=0;
 SELECT COUNT(*) > 0 FROM INFORMATION_SCHEMA.GLOBAL_STATUS;
-ERROR 08S01: WSREP has not yet prepared node for application use
+COUNT(*) > 0
+1
 SHOW STATUS LIKE 'wsrep_ready';
 Variable_name	Value
 wsrep_ready	OFF

mysql-test/suite/galera/r/galera_var_dirty_reads.result

@@ -33,11 +33,12 @@ SELECT 1;
 1
 1
 USE information_schema;
-ERROR 08S01: WSREP has not yet prepared node for application use
 SELECT * FROM information_schema.session_variables WHERE variable_name LIKE "wsrep_dirty_reads";
-ERROR 08S01: WSREP has not yet prepared node for application use
+VARIABLE_NAME	VARIABLE_VALUE
+WSREP_DIRTY_READS	OFF
 SELECT COUNT(*) >= 10 FROM performance_schema.events_statements_history;
-ERROR 08S01: WSREP has not yet prepared node for application use
+COUNT(*) >= 10
+1
 USE test;
 SELECT * FROM t1;
 i

mysql-test/suite/galera/t/galera_schema_dirty_reads.test

+#
+# Dirty reads from INFORMATION_SCHEMA tables.
+#
+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+--disable_info
+USE information_schema;
+SELECT * FROM SESSION_VARIABLES WHERE VARIABLE_NAME LIKE "wsrep_dirty_reads";
+SET GLOBAL wsrep_reject_queries=ALL;
+SELECT * FROM SESSION_VARIABLES WHERE VARIABLE_NAME LIKE "wsrep_dirty_reads";
+SET GLOBAL wsrep_reject_queries=NONE;
+SET SESSION wsrep_dirty_reads=TRUE;
+SELECT * FROM SESSION_VARIABLES WHERE VARIABLE_NAME LIKE "wsrep_dirty_reads";

mysql-test/suite/galera/t/galera_var_cluster_address.test

@@ -24,7 +24,6 @@ SET GLOBAL wsrep_cluster_address = 'foo://';
 
 SET SESSION wsrep_sync_wait=0;
 
---error ER_UNKNOWN_COM_ERROR
 SELECT COUNT(*) > 0 FROM INFORMATION_SCHEMA.GLOBAL_STATUS;
 
 # Must return 'OFF'

mysql-test/suite/galera/t/galera_var_dirty_reads.test

@@ -49,13 +49,10 @@ SELECT i, variable_name, variable_value FROM t1, information_schema.session_vari
 
 SELECT 1;
 
---error ER_UNKNOWN_COM_ERROR
 USE information_schema;
 
---error ER_UNKNOWN_COM_ERROR
 SELECT * FROM information_schema.session_variables WHERE variable_name LIKE "wsrep_dirty_reads";
 
---error ER_UNKNOWN_COM_ERROR
 SELECT COUNT(*) >= 10 FROM performance_schema.events_statements_history;
 
 --disable_query_log

mysql-test/suite/sys_vars/r/sysvars_wsrep.result

@@ -421,6 +421,20 @@ NUMERIC_BLOCK_SIZE	NULL
 ENUM_VALUE_LIST	OFF,ON
 READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	OPTIONAL
+VARIABLE_NAME	WSREP_REJECT_QUERIES
+SESSION_VALUE	NULL
+GLOBAL_VALUE	NONE
+GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+DEFAULT_VALUE	NONE
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	ENUM
+VARIABLE_COMMENT	Variable to set to reject queries
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	NONE,ALL,ALL_KILL
+READ_ONLY	NO
+COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	WSREP_REPLICATE_MYISAM
 SESSION_VALUE	NULL
 GLOBAL_VALUE	OFF

sql/sql_class.h

@@ -5475,6 +5475,14 @@ class select_dumpvar :public select_result_interceptor {
   sent by the user (ie: stored procedure).
 */
 #define CF_SKIP_QUESTIONS       (1U << 1)
+#ifdef WITH_WSREP
+/**
+  Do not check that wsrep snapshot is ready before allowing this command
+*/
+#define CF_SKIP_WSREP_CHECK     (1U << 2)
+#else
+#define CF_SKIP_WSREP_CHECK     0
+#endif /* WITH_WSREP */
 
 /**
   Do not check that wsrep snapshot is ready before allowing this command

sql/sql_parse.cc

 /* Copyright (c) 2000, 2017, Oracle and/or its affiliates.
-   Copyright (c) 2008, 2017, MariaDB
+   Copyright (c) 2008, 2018, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -284,6 +284,8 @@ void init_update_queries(void)
   server_command_flags[COM_QUERY]= CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_SET_OPTION]= CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_STMT_PREPARE]= CF_SKIP_QUESTIONS | CF_SKIP_WSREP_CHECK;
+  server_command_flags[COM_STMT_EXECUTE]= CF_SKIP_WSREP_CHECK;
+  server_command_flags[COM_STMT_FETCH]=   CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_STMT_CLOSE]= CF_SKIP_QUESTIONS | CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_STMT_RESET]= CF_SKIP_QUESTIONS | CF_SKIP_WSREP_CHECK;
   server_command_flags[COM_STMT_EXECUTE]= CF_SKIP_WSREP_CHECK;
@@ -887,6 +889,25 @@ void cleanup_items(Item *item)
 }
 
 
+#ifdef WITH_WSREP
+static bool wsrep_tables_accessible_when_detached(const TABLE_LIST *tables)
+{
+  for (const TABLE_LIST *table= tables; table; table= table->next_global)
+  {
+    TABLE_CATEGORY c;
+    LEX_STRING     db, tn;
+    lex_string_set(&db, table->db);
+    lex_string_set(&tn, table->table_name);
+    c= get_table_category(&db, &tn);
+    if (c != TABLE_CATEGORY_INFORMATION &&
+        c != TABLE_CATEGORY_PERFORMANCE)
+    {
+      return false;
+    }
+  }
+  return true;
+}
+#endif /* WITH_WSREP */
 #ifndef EMBEDDED_LIBRARY
 
 #ifdef WITH_WSREP
@@ -2659,14 +2680,18 @@ mysql_execute_command(THD *thd)
       We additionally allow all other commands that do not change data in
       case wsrep_dirty_reads is enabled.
     */
-    if (lex->sql_command != SQLCOM_SET_OPTION  &&
-        !wsrep_is_show_query(lex->sql_command) &&
-        !(thd->variables.wsrep_dirty_reads     &&
-          !is_update_query(lex->sql_command))  &&
-        !(lex->sql_command == SQLCOM_SELECT    &&
-          !all_tables)                         &&
-        !wsrep_node_is_ready(thd))
+    if (thd->variables.wsrep_on && !thd->wsrep_applier &&
+        !(wsrep_ready ||
+          (thd->variables.wsrep_dirty_reads &&
+           (sql_command_flags[lex->sql_command] & CF_CHANGES_DATA) == 0) ||
+          wsrep_tables_accessible_when_detached(all_tables)) &&
+         lex->sql_command != SQLCOM_SET_OPTION &&
+         !wsrep_is_show_query(lex->sql_command))
+    {
+      my_message(ER_UNKNOWN_COM_ERROR,
+                 "WSREP has not yet prepared node for application use", MYF(0));
       goto error;
+    }
   }
 #endif /* WITH_WSREP */
   status_var_increment(thd->status_var.com_stat[lex->sql_command]);

sql/sys_vars.cc

 /* Copyright (c) 2002, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2012, 2015, MariaDB
+   Copyright (c) 2012, 2018, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -4967,6 +4967,14 @@ static Sys_var_mybool Sys_wsrep_desync (
        ON_CHECK(wsrep_desync_check),
        ON_UPDATE(wsrep_desync_update));
 
+static const char *wsrep_reject_queries_names[]= { "NONE", "ALL", "ALL_KILL", NullS };
+static Sys_var_enum Sys_wsrep_reject_queries(
+       "wsrep_reject_queries", "Variable to set to reject queries",
+       GLOBAL_VAR(wsrep_reject_queries), CMD_LINE(OPT_ARG),
+       wsrep_reject_queries_names, DEFAULT(WSREP_REJECT_NONE),
+       NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
+       ON_UPDATE(wsrep_reject_queries_update));
+
 static const char *wsrep_binlog_format_names[]=
        {"MIXED", "STATEMENT", "ROW", "NONE", NullS};
 static Sys_var_enum Sys_wsrep_forced_binlog_format(

sql/wsrep_mysqld.h

@@ -80,6 +80,7 @@ extern const char* wsrep_notify_cmd;
 extern long        wsrep_max_protocol_version;
 extern ulong       wsrep_forced_binlog_format;
 extern my_bool     wsrep_desync;
+extern ulong       wsrep_reject_queries;
 extern my_bool     wsrep_replicate_myisam;
 extern ulong       wsrep_mysql_replication_bundle;
 extern my_bool     wsrep_restart_slave;
@@ -92,6 +93,12 @@ extern bool        wsrep_gtid_mode;
 extern uint32      wsrep_gtid_domain_id;
 extern bool        wsrep_dirty_reads;
 
+enum enum_wsrep_reject_types {
+  WSREP_REJECT_NONE,    /* nothing rejected */
+  WSREP_REJECT_ALL,     /* reject all queries, with UNKNOWN_COMMAND error */
+  WSREP_REJECT_ALL_KILL /* kill existing connections and reject all queries*/
+};
+
 enum enum_wsrep_OSU_method {
     WSREP_OSU_TOI,
     WSREP_OSU_RSU,

sql/wsrep_var.cc

@@ -34,6 +34,7 @@ const  char* wsrep_node_name        = 0;
 const  char* wsrep_node_address     = 0;
 const  char* wsrep_node_incoming_address = 0;
 const  char* wsrep_start_position   = 0;
+ulong   wsrep_reject_queries;
 
 static long wsrep_prev_slave_threads = wsrep_slave_threads;
 
@@ -384,6 +385,30 @@ void wsrep_provider_options_init(const char* value)
   wsrep_provider_options = (value) ? my_strdup(value, MYF(0)) : NULL;
 }
 
+bool wsrep_reject_queries_update(sys_var *self, THD* thd, enum_var_type type)
+{
+    switch (wsrep_reject_queries) {
+        case WSREP_REJECT_NONE:
+            wsrep_ready_set(TRUE); 
+            WSREP_INFO("Allowing client queries due to manual setting");
+            break;
+        case WSREP_REJECT_ALL:
+            wsrep_ready_set(FALSE);
+            WSREP_INFO("Rejecting client queries due to manual setting");
+            break;
+        case WSREP_REJECT_ALL_KILL:
+            wsrep_ready_set(FALSE);
+            wsrep_close_client_connections(FALSE);
+            WSREP_INFO("Rejecting client queries and killing connections due to manual setting");
+            break;
+        default:
+          WSREP_INFO("Unknown value for wsrep_reject_queries: %lu",
+                     wsrep_reject_queries);
+            return true;
+    }
+    return false;
+}
+
 static int wsrep_cluster_address_verify (const char* cluster_address_str)
 {
   /* There is no predefined address format, it depends on provider. */

sql/wsrep_var.h

@@ -93,6 +93,7 @@ extern bool wsrep_desync_update              UPDATE_ARGS;
 
 extern bool wsrep_max_ws_size_check          CHECK_ARGS;
 extern bool wsrep_max_ws_size_update         UPDATE_ARGS;
+extern bool wsrep_reject_queries_update      UPDATE_ARGS;
 
 #else  /* WITH_WSREP */