MDEV-8464 : ALTER VIEW not replicated in some cases

In galera, like other DDLs, CREATE/ALTER VIEW commands are recreated
and replicated during parsing. The ALGORITHM clause is internally set
to VIEW_ALGORITHM_INHERIT if its not explicitly specified by the user.
But since its not a valid type to be used in a command, it leads to an
assertion failure. The solution is to not include the ALGORITHM clause
in the command if its not explicitly specified (or INHERIT).

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

+#
+# MDEV-8464 : ALTER VIEW not replicated in some cases
+#
+# On node_1
+USE test;
+CREATE TABLE t1(i INT) ENGINE=INNODB;
+CREATE DEFINER=CURRENT_USER VIEW v1 AS SELECT * FROM t1;
+CREATE ALGORITHM=MERGE VIEW v2 AS SELECT * FROM t1;
+CREATE ALGORITHM=TEMPTABLE VIEW v3 AS SELECT * FROM t1;
+CREATE ALGORITHM=UNDEFINED DEFINER=CURRENT_USER VIEW v4 AS SELECT * FROM t1;
+# On node_2
+USE test;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+SHOW CREATE VIEW v2;
+View	Create View	character_set_client	collation_connection
+v2	CREATE ALGORITHM=MERGE DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v2` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+SHOW CREATE VIEW v3;
+View	Create View	character_set_client	collation_connection
+v3	CREATE ALGORITHM=TEMPTABLE DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v3` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+SHOW CREATE VIEW v4;
+View	Create View	character_set_client	collation_connection
+v4	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v4` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+# On node_1
+ALTER ALGORITHM=MERGE VIEW v1 AS SELECT * FROM t1;
+ALTER ALGORITHM=UNDEFINED VIEW v2 AS SELECT * FROM t1;
+ALTER DEFINER=CURRENT_USER VIEW v3 AS SELECT * FROM t1;
+ALTER ALGORITHM=TEMPTABLE DEFINER=CURRENT_USER VIEW v4 AS SELECT * FROM t1;
+# On node_2
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=MERGE DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+SHOW CREATE VIEW v2;
+View	Create View	character_set_client	collation_connection
+v2	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v2` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+SHOW CREATE VIEW v3;
+View	Create View	character_set_client	collation_connection
+v3	CREATE ALGORITHM=TEMPTABLE DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v3` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+SHOW CREATE VIEW v4;
+View	Create View	character_set_client	collation_connection
+v4	CREATE ALGORITHM=TEMPTABLE DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v4` AS select `t1`.`i` AS `i` from `t1`	latin1	latin1_swedish_ci
+# Cleanup
+DROP VIEW v1, v2, v3, v4;
+DROP TABLE t1;
+# End of tests

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

+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+
+--echo #
+--echo # MDEV-8464 : ALTER VIEW not replicated in some cases
+--echo #
+--echo # On node_1
+--connection node_1
+USE test;
+CREATE TABLE t1(i INT) ENGINE=INNODB;
+CREATE DEFINER=CURRENT_USER VIEW v1 AS SELECT * FROM t1;
+CREATE ALGORITHM=MERGE VIEW v2 AS SELECT * FROM t1;
+CREATE ALGORITHM=TEMPTABLE VIEW v3 AS SELECT * FROM t1;
+CREATE ALGORITHM=UNDEFINED DEFINER=CURRENT_USER VIEW v4 AS SELECT * FROM t1;
+
+--echo # On node_2
+--connection node_2
+USE test;
+SHOW CREATE VIEW v1;
+SHOW CREATE VIEW v2;
+SHOW CREATE VIEW v3;
+SHOW CREATE VIEW v4;
+
+--echo # On node_1
+--connection node_1
+ALTER ALGORITHM=MERGE VIEW v1 AS SELECT * FROM t1;
+ALTER ALGORITHM=UNDEFINED VIEW v2 AS SELECT * FROM t1;
+ALTER DEFINER=CURRENT_USER VIEW v3 AS SELECT * FROM t1;
+ALTER ALGORITHM=TEMPTABLE DEFINER=CURRENT_USER VIEW v4 AS SELECT * FROM t1;
+
+--echo # On node_2
+--connection node_2
+SHOW CREATE VIEW v1;
+SHOW CREATE VIEW v2;
+SHOW CREATE VIEW v3;
+SHOW CREATE VIEW v4;
+
+--echo # Cleanup
+DROP VIEW v1, v2, v3, v4;
+DROP TABLE t1;
+
+--echo # End of tests
+

sql/sql_show.cc

@@ -119,9 +119,6 @@ static void get_cs_converted_string_value(THD *thd,
                                           bool use_hex);
 #endif
 
-static void
-append_algorithm(TABLE_LIST *table, String *buff);
-
 static COND * make_cond_for_info_schema(COND *cond, TABLE_LIST *table);
 
 /***************************************************************************
@@ -1972,32 +1969,30 @@ static void store_key_options(THD *thd, String *packet, TABLE *table,
   }
 }
 
-
-void
-view_store_options(THD *thd, TABLE_LIST *table, String *buff)
-{
-  append_algorithm(table, buff);
-  append_definer(thd, buff, &table->definer.user, &table->definer.host);
-  if (table->view_suid)
-    buff->append(STRING_WITH_LEN("SQL SECURITY DEFINER "));
-  else
-    buff->append(STRING_WITH_LEN("SQL SECURITY INVOKER "));
-}
-
-
 /*
-  Append DEFINER clause to the given buffer.
+  Append ALGORITHM clause to the given buffer.
 
   SYNOPSIS
-    append_definer()
-    thd           [in] thread handle
-    buffer        [inout] buffer to hold DEFINER clause
-    definer_user  [in] user name part of definer
-    definer_host  [in] host name part of definer
+    append_algorithm()
+    table         [in]    table list
+    buff          [inout] buffer to hold the ALGORITHM clause
+    check_inherit [in]    if true, do nothing if algorithm is INHERIT
 */
 
-static void append_algorithm(TABLE_LIST *table, String *buff)
+static void append_algorithm(TABLE_LIST *table, String *buff,
+                             bool check_inherit)
 {
+  int16 algorithm= (int16) table->algorithm;
+
+  DBUG_ENTER("append_algorithm");
+
+  /*
+    Handle a special case when ALGORITHM is not specified, in which case we
+    simply return.
+  */
+  if (check_inherit && (algorithm == VIEW_ALGORITHM_INHERIT))
+    DBUG_VOID_RETURN;
+
   buff->append(STRING_WITH_LEN("ALGORITHM="));
   switch ((int16)table->algorithm) {
   case VIEW_ALGORITHM_UNDEFINED:
@@ -2012,6 +2007,8 @@ static void append_algorithm(TABLE_LIST *table, String *buff)
   default:
     DBUG_ASSERT(0); // never should happen
   }
+
+  DBUG_VOID_RETURN;
 }
 
 /*
@@ -2035,6 +2032,23 @@ void append_definer(THD *thd, String *buffer, const LEX_STRING *definer_user,
   buffer->append(' ');
 }
 
+void
+view_store_options4(THD *thd, TABLE_LIST *table, String *buff,
+                    bool check_inherit)
+{
+  append_algorithm(table, buff, check_inherit);
+  append_definer(thd, buff, &table->definer.user, &table->definer.host);
+  if (table->view_suid)
+    buff->append(STRING_WITH_LEN("SQL SECURITY DEFINER "));
+  else
+    buff->append(STRING_WITH_LEN("SQL SECURITY INVOKER "));
+}
+
+void
+view_store_options(THD *thd, TABLE_LIST *table, String *buff)
+{
+  view_store_options4(thd, table, buff, false);
+}
 
 int
 view_store_create_info(THD *thd, TABLE_LIST *table, String *buff)

sql/sql_show.h

@@ -115,6 +115,8 @@ void free_status_vars();
 void reset_status_vars();
 bool show_create_trigger(THD *thd, const sp_name *trg_name);
 void view_store_options(THD *thd, TABLE_LIST *table, String *buff);
+void view_store_options4(THD *thd, TABLE_LIST *table, String *buff,
+                         bool check_inherit);
 
 void init_fill_schema_files_row(TABLE* table);
 bool schema_table_store_record(THD *thd, TABLE *table);

sql/wsrep_mysqld.cc

@@ -1193,7 +1193,7 @@ create_view_query(THD *thd, uchar** buf, size_t* buf_len)
     views->view_suid    = lex->create_view_suid;
     views->with_check   = lex->create_view_check;
 
-    view_store_options(thd, views, &buff);
+    view_store_options4(thd, views, &buff, true);
     buff.append(STRING_WITH_LEN("VIEW "));
     /* Test if user supplied a db (ie: we did not use thd->db) */
     if (views->db && views->db[0] &&