bk commit into 5.1 tree (evgen:1.2518) BUG#28427

[eugene]

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ChangeSet@stripped, 2007-06-02 01:21:18+04:00, evgen@stripped +3 -0
  Bug#28427: Columns were renamed instead of moving by ALTER TABLE.
  
  To avoid unnecessary work the mysql_alter_table function takes the
  list of table fields and applies all changes to it (drops/moves/renames/etc).
  Then this function compares the new list and the old one. If the changes
  require only .frm to be modified then the actual data isn't copied. To detect
  changes all columns attributes but names are compared. When a column has been
  moved and has replaced another column with the same attributes except name
  the mysql_alter_table function wrongly decides that two fields has been just
  renamed. As a result the data from the moved column and from all columns
  after it is not copied.
  
  Now the mysql_alter_table function forces table data copying by setting
  the need_copy_table flag when it finds a moved column. The flag is set at
  the stage when the modified fields are created.
  

  mysql-test/r/alter_table.result@stripped, 2007-06-02 01:21:12+04:00, evgen@stripped +14 -0
    Added a test case for the bug#28427: Columns were renamed instead of moving by ALTER TABLE.

  mysql-test/t/alter_table.test@stripped, 2007-06-02 01:21:13+04:00, evgen@stripped +12 -0
    Added a test case for the bug#28427: Columns were renamed instead of moving by ALTER TABLE.

  sql/sql_table.cc@stripped, 2007-06-02 01:20:57+04:00, evgen@stripped +4 -1
    Bug#28427: Columns were renamed instead of moving by ALTER TABLE.
    Now the mysql_alter_table function forces table data copying by setting
    the need_copy_table flag when it finds a moved column. The flag is set at
    the stage when the modified fields are created.

# 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:	evgen
# Host:	moonbone.local
# Root:	/mnt/gentoo64/work/28427-bug-5.1-opt-mysql

--- 1.419/sql/sql_table.cc	2007-06-01 08:20:08 +04:00
+++ 1.420/sql/sql_table.cc	2007-06-02 01:20:57 +04:00
@@ -5932,6 +5932,7 @@ view_err:
         goto err;
       }
       find_it.after(def);			// Put element after this
+      need_copy_table= ALTER_TABLE_DATA_CHANGED;
     }
   }
   if (alter_info->alter_list.elements)
@@ -6170,12 +6171,14 @@ view_err:
            (uint*) thd->alloc(sizeof(uint) * prepared_key_list.elements)))
       goto err;
     /* Check how much the tables differ. */
-    need_copy_table= compare_tables(table, &prepared_create_list,
+    bool res= compare_tables(table, &prepared_create_list,
                                     key_info_buffer, key_count,
                                     create_info, alter_info, order_num,
                                     index_drop_buffer, &index_drop_count,
                                     index_add_buffer, &index_add_count,
                                     varchar);
+    if (!need_copy_table)
+      need_copy_table= res;
   }
 
   /*

--- 1.82/mysql-test/r/alter_table.result	2007-05-23 13:46:08 +04:00
+++ 1.83/mysql-test/r/alter_table.result	2007-06-02 01:21:12 +04:00
@@ -1103,3 +1103,17 @@ Field	Type	Null	Key	Default	Extra
 unsigned_int_field	bigint(20) unsigned	NO	MUL		
 char_field	char(10)	YES		NULL	
 DROP TABLE t2;
+CREATE TABLE t1 (f1 INT, f2 INT, f3 INT);
+INSERT INTO t1 VALUES (1, 2, NULL);
+SELECT * FROM t1;
+f1	f2	f3
+1	2	NULL
+ALTER TABLE t1 MODIFY COLUMN f3 INT AFTER f1;
+SELECT * FROM t1;
+f1	f3	f2
+1	NULL	2
+ALTER TABLE t1 MODIFY COLUMN f3 INT AFTER f2;
+SELECT * FROM t1;
+f1	f2	f3
+1	2	NULL
+DROP TABLE t1;

--- 1.65/mysql-test/t/alter_table.test	2007-05-23 13:46:08 +04:00
+++ 1.66/mysql-test/t/alter_table.test	2007-06-02 01:21:13 +04:00
@@ -839,3 +839,15 @@ ALTER TABLE t2 MODIFY unsigned_int_field
 DESCRIBE t2;
 
 DROP TABLE t2;
+
+#
+# Bug#28427: Columns were renamed instead of moving by ALTER TABLE.
+#
+CREATE TABLE t1 (f1 INT, f2 INT, f3 INT);
+INSERT INTO t1 VALUES (1, 2, NULL);
+SELECT * FROM t1;
+ALTER TABLE t1 MODIFY COLUMN f3 INT AFTER f1;
+SELECT * FROM t1;
+ALTER TABLE t1 MODIFY COLUMN f3 INT AFTER f2;
+SELECT * FROM t1;
+DROP TABLE t1;