From: Dmitry Lenev
Date: June 16 2011 11:47pm
Subject: bzr push into mysql-trunk branch (Dmitry.Lenev:3216 to 3217) Bug#12652385
List-Archive: http://lists.mysql.com/commits/139379
X-Bug: 12652385
Message-Id: <20110616234702.B28C67406A5@bandersnatch>
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 3217 Dmitry Lenev	2011-06-17 [merge]
      Merged fix for bug #12652385 - "61493: REORDERING
      COLUMNS TO POSITION FIRST CAN CAUSE DATA TO BE
      CORRUPTED" into mysql-trunk.

    modified:
      mysql-test/r/alter_table.result
      mysql-test/t/alter_table.test
      sql/sql_table.cc
 3216 Matthias Leich	2011-06-16 [merge]
      Upmerge mysql-5.5 -> mysql-trunk

    modified:
      mysql-test/suite/perfschema/include/cleanup_helper.inc
      mysql-test/suite/perfschema/include/upgrade_check.inc
      mysql-test/suite/perfschema/r/selects.result
      mysql-test/suite/perfschema/t/selects.test
=== modified file 'mysql-test/r/alter_table.result'
--- a/mysql-test/r/alter_table.result	2011-05-04 07:51:15 +0000
+++ b/mysql-test/r/alter_table.result	2011-06-16 23:45:58 +0000
@@ -1345,6 +1345,35 @@ DROP TABLE t1;
 CREATE TABLE t1 (a TEXT, id INT, b INT);
 ALTER TABLE t1 DROP COLUMN a, ADD COLUMN c TEXT FIRST;
 DROP TABLE t1;
+#
+# Test for bug #12652385 - "61493: REORDERING COLUMNS TO POSITION
+#                           FIRST CAN CAUSE DATA TO BE CORRUPTED".
+#
+drop table if exists t1;
+# Use MyISAM engine as the fact that InnoDB doesn't support
+# in-place ALTER TABLE in cases when columns are being renamed
+# hides some bugs.
+create table t1 (i int, j int) engine=myisam;
+insert into t1 value (1, 2);
+# First, test for original problem described in the bug report.
+select * from t1;
+i	j
+1	2
+# Change of column order by the below ALTER TABLE statement should
+# affect both column names and column contents.
+alter table t1 modify column j int first;
+select * from t1;
+j	i
+2	1
+# Now test for similar problem with the same root.
+# The below ALTER TABLE should change not only the name but
+# also the value for the last column of the table.
+alter table t1 drop column i, add column k int default 0;
+select * from t1;
+j	k
+2	0
+# Clean-up.
+drop table t1;
 End of 5.1 tests
 CREATE TABLE t1(c CHAR(10), 
 i INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY);

=== modified file 'mysql-test/t/alter_table.test'
--- a/mysql-test/t/alter_table.test	2011-05-04 07:51:15 +0000
+++ b/mysql-test/t/alter_table.test	2011-06-16 23:45:58 +0000
@@ -1073,6 +1073,33 @@ ALTER TABLE t1 DROP COLUMN a, ADD COLUMN
 DROP TABLE t1;
 
 
+--echo #
+--echo # Test for bug #12652385 - "61493: REORDERING COLUMNS TO POSITION
+--echo #                           FIRST CAN CAUSE DATA TO BE CORRUPTED".
+--echo #
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+--echo # Use MyISAM engine as the fact that InnoDB doesn't support
+--echo # in-place ALTER TABLE in cases when columns are being renamed
+--echo # hides some bugs.
+create table t1 (i int, j int) engine=myisam;
+insert into t1 value (1, 2);
+--echo # First, test for original problem described in the bug report.
+select * from t1;
+--echo # Change of column order by the below ALTER TABLE statement should
+--echo # affect both column names and column contents.
+alter table t1 modify column j int first;
+select * from t1;
+--echo # Now test for similar problem with the same root.
+--echo # The below ALTER TABLE should change not only the name but
+--echo # also the value for the last column of the table.
+alter table t1 drop column i, add column k int default 0;
+select * from t1;
+--echo # Clean-up.
+drop table t1;
+
+
 --echo End of 5.1 tests
 
 #

=== modified file 'sql/sql_table.cc'
--- a/sql/sql_table.cc	2011-06-15 22:31:43 +0000
+++ b/sql/sql_table.cc	2011-06-16 23:45:58 +0000
@@ -5577,6 +5577,12 @@ mysql_prepare_alter_table(THD *thd, TABL
     if (drop)
     {
       drop_it.remove();
+      /*
+        ALTER TABLE DROP COLUMN always changes table data even in cases
+        when new version of the table has the same structure as the old
+        one.
+      */
+      alter_info->change_level= ALTER_TABLE_DATA_CHANGED;
       continue;
     }
     /* Check if field is changed */
@@ -5654,7 +5660,14 @@ mysql_prepare_alter_table(THD *thd, TABL
     if (!def->after)
       new_create_list.push_back(def);
     else if (def->after == first_keyword)
+    {
       new_create_list.push_front(def);
+      /*
+        Re-ordering columns in table can't be done using in-place algorithm
+        as it always changes table data.
+      */
+      alter_info->change_level= ALTER_TABLE_DATA_CHANGED;
+    }
     else
     {
       Create_field *find;
@@ -5670,6 +5683,10 @@ mysql_prepare_alter_table(THD *thd, TABL
         goto err;
       }
       find_it.after(def);			// Put element after this
+      /*
+        Re-ordering columns in table can't be done using in-place algorithm
+        as it always changes table data.
+      */
       alter_info->change_level= ALTER_TABLE_DATA_CHANGED;
     }
   }

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