BUG#27998 - mysqld crashed when executing INSERT DELAYED

            on a BLACKHOLE table

Using INSERT DELAYED on BLACKHOLE tables could lead to server
crash.

This happens because delayed thread wants to upgrade a lock,
but BLACKHOLE tables do not have locks at all.

This patch rejects attempts to use INSERT DELAYED on MERGE
tables.


mysql-test/r/blackhole.result:
  A test case for BUG#27998.
mysql-test/t/blackhole.test:
  A test case for BUG#27998.
sql/ha_blackhole.h:
  Removed HA_CAN_INSERT_DELAYED flag from table_flags().
  The insert delayed thread upgrades the lock. Hence it is
  incapable to handle BLACKHOLE tables, which do not have
  locks at all.

mysql-test/r/blackhole.result

@@ -123,3 +123,7 @@ master-bin.000001	#	Query	1	#	use `test`; create table t3 like t1
 master-bin.000001	#	Query	1	#	use `test`; insert into t1 select * from t3
 master-bin.000001	#	Query	1	#	use `test`; replace into t1 select * from t3
 drop table t1,t2,t3;
+CREATE TABLE t1(a INT) ENGINE=BLACKHOLE;
+INSERT DELAYED INTO t1 VALUES(1);
+ERROR HY000: Table storage engine for 't1' doesn't have this option
+DROP TABLE t1;

mysql-test/t/blackhole.test

@@ -126,4 +126,13 @@ show binlog events;
 
 drop table t1,t2,t3;
 
+#
+# BUG#27998 - mysqld crashed when executing INSERT DELAYED on a BLACKHOLE
+#             table
+#
+CREATE TABLE t1(a INT) ENGINE=BLACKHOLE;
+--error 1031
+INSERT DELAYED INTO t1 VALUES(1);
+DROP TABLE t1;
+
 # End of 4.1 tests

sql/ha_blackhole.h

@@ -46,8 +46,7 @@ class ha_blackhole: public handler
   {
     return(HA_NULL_IN_KEY | HA_CAN_FULLTEXT | HA_CAN_SQL_HANDLER |
            HA_DUPP_POS | HA_CAN_INDEX_BLOBS | HA_AUTO_PART_KEY |
-           HA_FILE_BASED | HA_CAN_GEOMETRY | HA_READ_RND_SAME |
-           HA_CAN_INSERT_DELAYED);
+           HA_FILE_BASED | HA_CAN_GEOMETRY | HA_READ_RND_SAME);
   }
   ulong index_flags(uint inx, uint part, bool all_parts) const
   {