Merge xiphis.org:/home/antony/work2/p1-bug10952.1

into  xiphis.org:/home/antony/work2/mysql-5.0-engines-merge

mysql-test/r/blackhole.result

@@ -123,3 +123,11 @@ 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;
+drop table if exists t1;
+Warnings:
+Note	1051	Unknown table 't1'
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+alter table t1 engine=blackhole;
+ERROR HY000: Table storage engine for 't1' doesn't have this option
+drop table t1;

mysql-test/r/merge.result

@@ -768,3 +768,11 @@ Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 test.t2	check	status	OK
 drop table t1, t2, t3;
+drop table if exists t1;
+Warnings:
+Note	1051	Unknown table 't1'
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+alter table t1 engine=MERGE;
+ERROR HY000: Table storage engine for 't1' doesn't have this option
+drop table t1;

mysql-test/t/blackhole.test

@@ -128,3 +128,15 @@ show binlog events;
 drop table t1,t2,t3;
 
 # End of 4.1 tests
+
+#
+# BUG#10952 - alter table ... lost data without errors and warnings
+#
+drop table if exists t1;
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+--error 1031
+alter table t1 engine=blackhole;
+drop table t1;
+
+# End of 5.0 tests

mysql-test/t/merge.test

@@ -379,3 +379,15 @@ check table t1, t2;
 drop table t1, t2, t3;
 
 # End of 4.1 tests
+
+#
+# BUG#10952 - alter table ... lost data without errors and warnings
+#
+drop table if exists t1;
+create table t1 (c char(20)) engine=MyISAM;
+insert into t1 values ("Monty"),("WAX"),("Walrus");
+--error 1031
+alter table t1 engine=MERGE;
+drop table t1;
+
+# End of 5.0 tests

sql/ha_blackhole.cc

@@ -47,7 +47,7 @@ handlerton blackhole_hton= {
   NULL,    /* create_cursor_read_view */
   NULL,    /* set_cursor_read_view */
   NULL,    /* close_cursor_read_view */
-  HTON_CAN_RECREATE
+  HTON_CAN_RECREATE | HTON_ALTER_CANNOT_CREATE
 };
 
 /*****************************************************************************

sql/ha_myisammrg.cc

@@ -55,7 +55,7 @@ handlerton myisammrg_hton= {
   NULL,    /* create_cursor_read_view */
   NULL,    /* set_cursor_read_view */
   NULL,    /* close_cursor_read_view */
-  HTON_CAN_RECREATE
+  HTON_CAN_RECREATE | HTON_ALTER_CANNOT_CREATE
 };
 
 

sql/handler.h

@@ -409,6 +409,7 @@ struct show_table_alias_st {
 #define HTON_ALTER_NOT_SUPPORTED     (1 << 1) //Engine does not support alter
 #define HTON_CAN_RECREATE            (1 << 2) //Delete all is used fro truncate
 #define HTON_HIDDEN                  (1 << 3) //Engine does not appear in lists
+#define HTON_ALTER_CANNOT_CREATE     (1 << 4) //Cannot use alter to create
 
 typedef struct st_thd_trans
 {

sql/sql_table.cc

@@ -3324,7 +3324,9 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
 
   DBUG_PRINT("info", ("old type: %d  new type: %d", old_db_type, new_db_type));
   if (ha_check_storage_engine_flag(old_db_type, HTON_ALTER_NOT_SUPPORTED) ||
-      ha_check_storage_engine_flag(new_db_type, HTON_ALTER_NOT_SUPPORTED))
+      ha_check_storage_engine_flag(new_db_type, HTON_ALTER_NOT_SUPPORTED) ||
+      (old_db_type != new_db_type &&
+       ha_check_storage_engine_flag(new_db_type, HTON_ALTER_CANNOT_CREATE)))
   {
     DBUG_PRINT("info", ("doesn't support alter"));
     my_error(ER_ILLEGAL_HA, MYF(0), table_name);