diff --git a/mysql-test/r/alter_table.result b/mysql-test/r/alter_table.result index 004e2031fb1..674238b14cd 100644 --- a/mysql-test/r/alter_table.result +++ b/mysql-test/r/alter_table.result @@ -1345,4 +1345,33 @@ 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 diff --git a/mysql-test/t/alter_table.test b/mysql-test/t/alter_table.test index 4989a6c380c..2a8ac2a00d6 100644 --- a/mysql-test/t/alter_table.test +++ b/mysql-test/t/alter_table.test @@ -1073,4 +1073,31 @@ ALTER TABLE t1 DROP COLUMN a, ADD COLUMN c TEXT FIRST; 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 diff --git a/sql/sql_table.cc b/sql/sql_table.cc index 58e2684e5b7..077f00f9ea8 100644 --- a/sql/sql_table.cc +++ b/sql/sql_table.cc @@ -6170,6 +6170,12 @@ mysql_prepare_alter_table(THD *thd, TABLE *table, 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 */ @@ -6247,7 +6253,14 @@ mysql_prepare_alter_table(THD *thd, TABLE *table, 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; @@ -6263,6 +6276,10 @@ mysql_prepare_alter_table(THD *thd, TABLE *table, 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; } }