A follow up patch for WL#5000: add a test case

and a comment for the case when a connection
issuing FLUSH TABLES <list> WITH READ LOCK
has an open handler.

mysql-test/r/flush.result

@@ -279,3 +279,28 @@ drop temporary table v1;
 unlock tables;
 drop view v2, v3;
 drop table t1, v1;
+# 
+# FLUSH TABLES <list> WITH READ LOCK and HANDLER
+# 
+drop table if exists t1;
+create table t1 (a int, key a (a));
+insert into t1 (a) values (1), (2), (3);
+handler t1 open;
+handler t1 read a next;
+a
+1
+handler t1 read a next;
+a
+2
+flush tables t1 with read lock;
+handler t1 read a next;
+ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
+unlock tables;
+#
+# Sic: lost handler position.
+#
+handler t1 read a next;
+a
+1
+handler t1 close;
+drop table t1;

mysql-test/t/flush.test

@@ -407,3 +407,26 @@ drop temporary table v1;
 unlock tables;
 drop view v2, v3;
 drop table t1, v1;
+
+
+--echo # 
+--echo # FLUSH TABLES <list> WITH READ LOCK and HANDLER
+--echo # 
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+create table t1 (a int, key a (a));
+insert into t1 (a) values (1), (2), (3);
+handler t1 open;
+handler t1 read a next;
+handler t1 read a next;
+flush tables t1 with read lock;
+--error ER_LOCK_OR_ACTIVE_TRANSACTION
+handler t1 read a next;
+unlock tables;
+--echo #
+--echo # Sic: lost handler position.
+--echo #
+handler t1 read a next;
+handler t1 close;
+drop table t1;

sql/sql_parse.cc

@@ -1750,6 +1750,17 @@ int prepare_schema_table(THD *thd, LEX *lex, Table_ident *table_ident,
   If a temporary table with such name exists, it's ignored:
   if there is a base table, it's used, otherwise ER_NO_SUCH_TABLE
   is returned.
+
+  Implicit commit
+  ---------------
+  This statement causes an implicit commit before and
+  after it.
+
+  HANDLER SQL
+  -----------
+  If this connection has HANDLERs open against
+  some of the tables being FLUSHed, these handlers
+  are implicitly flushed (lose their position).
 */
 
 static bool flush_tables_with_read_lock(THD *thd, TABLE_LIST *all_tables)