bk commit into 4.1 tree (marko:1.2170) BUG#5574

[Marko Mäkelä]

Below is the list of changes that have just been committed into a local
4.1 repository of marko. When marko does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
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see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet
  1.2170 05/04/07 12:16:41 marko@stripped +4 -0
  InnoDB: Prevent ALTER TABLE ... ENGINE=...
  if there are foreign key constraints on the table. (Bug #5574)

  sql/sql_table.cc
    1.277 05/04/07 12:16:34 marko@stripped +4 -0
    Check handler::can_switch_engines() before switching storage engines

  sql/handler.h
    1.136 05/04/07 12:16:34 marko@stripped +2 -0
    Add method can_switch_engines()

  sql/ha_innodb.h
    1.79 05/04/07 12:16:34 marko@stripped +1 -0
    Add method can_switch_engines()

  sql/ha_innodb.cc
    1.188 05/04/07 12:16:34 marko@stripped +26 -0
    Add method can_switch_engines()

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	marko
# Host:	hundin.mysql.fi
# Root:	/home/marko/mysql-4.1

--- 1.135/sql/handler.h	Fri Mar 25 22:36:02 2005
+++ 1.136/sql/handler.h	Thu Apr  7 12:16:34 2005
@@ -450,6 +450,8 @@
   virtual void append_create_info(String *packet) {}
   virtual char* get_foreign_key_create_info()
   { return(NULL);}  /* gets foreign key create string from InnoDB */
+  /* used in ALTER TABLE; 1 if changing storage engine is allowed */
+  virtual bool can_switch_engines() { return 1; }
   /* used in REPLACE; is > 0 if table is referred by a FOREIGN KEY */
   virtual uint referenced_by_foreign_key() { return 0;}
   virtual void init_table_handle_for_HANDLER()

--- 1.276/sql/sql_table.cc	Sat Apr  2 21:28:51 2005
+++ 1.277/sql/sql_table.cc	Thu Apr  7 12:16:34 2005
@@ -3109,6 +3109,10 @@
   /* Safety fix for innodb */
   if (lower_case_table_names)
     my_casedn_str(files_charset_info, tmp_name);
+  if (new_db_type != old_db_type && !table->file->can_switch_engines()) {
+    my_error(ER_ROW_IS_REFERENCED, MYF(0));
+    goto err;
+  }
   create_info->db_type=new_db_type;
   if (!create_info->comment)
     create_info->comment=table->comment;

--- 1.187/sql/ha_innodb.cc	Mon Apr  4 19:41:36 2005
+++ 1.188/sql/ha_innodb.cc	Thu Apr  7 12:16:34 2005
@@ -4789,6 +4789,32 @@
   	return(str);
 }
 
+/*********************************************************************
+Checks if ALTER TABLE may change the storage engine of the table.
+Changing storage engines is not allowed for tables for which there
+are foreign key constraints (parent or child tables). */
+
+bool
+ha_innobase::can_switch_engines(void)
+/*=================================*/
+{
+	row_prebuilt_t* prebuilt	= (row_prebuilt_t*) innobase_prebuilt;
+	bool	can_switch;
+
+ 	DBUG_ENTER("ha_innobase::can_switch_engines");
+	prebuilt->trx->op_info =
+			"determining if there are foreign key constraints";
+	row_mysql_lock_data_dictionary(prebuilt->trx);
+
+	can_switch = !UT_LIST_GET_FIRST(prebuilt->table->referenced_list)
+			&& !UT_LIST_GET_FIRST(prebuilt->table->foreign_list);
+
+	row_mysql_unlock_data_dictionary(prebuilt->trx);
+	prebuilt->trx->op_info = "";
+
+	DBUG_RETURN(can_switch);
+}
+
 /***********************************************************************
 Checks if a table is referenced by a foreign key. The MySQL manual states that
 a REPLACE is either equivalent to an INSERT, or DELETE(s) + INSERT. Only a

--- 1.78/sql/ha_innodb.h	Tue Mar  1 16:08:27 2005
+++ 1.79/sql/ha_innodb.h	Thu Apr  7 12:16:34 2005
@@ -161,6 +161,7 @@
 	int check(THD* thd, HA_CHECK_OPT* check_opt);
         char* update_table_comment(const char* comment);
 	char* get_foreign_key_create_info();
+	bool can_switch_engines();
   	uint referenced_by_foreign_key();
 	void free_foreign_key_create_info(char* str);	
   	THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,