bzr commit into mysql-6.0 branch (satya.bn:2900) Bug#33696

[Satya B]

#At file:///home/satya/WORK/mysql-6.0-bugteam-33696/

 2900 Satya B	2008-11-05
      Fix for Bug#33696 - CSV storage engine allows nullable columns via ALTER TABLE
statements
      
      Problem:
      After the fast online-alter table changes, CSV engine allows nullable columns via
alter table and also the existing non-null columns  can be modified to null columns.
      All columns in CSV Engine should be NON-NULL always.
      
      How it was solved:
      Found that we evaluate the changes that will be made to altered table. During this
evaluation, we check for the behaviour of the new fields in temporary altered table with
the fields in the original table and maintain as table_changes. This is passed to storage
engines along with the new information. Storage engines can add further checks and return
the compatibility state.CSV Engine has this information but ignores it and returns always
true. Changed the behaviour to return compatible or not based on the information passed
from the server.
      
      In sql_table.cc: mysql_alter_table(...), create_altered_table(...) creates the
altered table and table->file->check_if_supported_alter(..) checks if a table can
be altered on-line
      
      Note:
      The csv_alter_table exists in the repository and was disabled due to this bug.
added:
  mysql-test/r/csv_alter_table.result
modified:
  mysql-test/t/disabled.def
  storage/csv/ha_tina.cc

per-file messages:
  mysql-test/r/csv_alter_table.result
    Result file for csv_alter_table.test(the test file exists in the main branch)
  mysql-test/t/disabled.def
    Enabling the disabled test csv_alter_table.test
  storage/csv/ha_tina.cc
    Fixed check_if_incompatible_data to return correct compatibility state based on the
information provided from server.
=== added file 'mysql-test/r/csv_alter_table.result'
--- a/mysql-test/r/csv_alter_table.result	1970-01-01 00:00:00 +0000
+++ b/mysql-test/r/csv_alter_table.result	2008-11-05 12:03:55 +0000
@@ -0,0 +1,40 @@
+# ===== csv_alter_table.1 =====
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (a int NOT NULL) ENGINE = CSV;
+ALTER TABLE t1 ADD COLUMN b CHAR(5) NOT NULL;
+DESC t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	NO		NULL	
+b	char(5)	NO		NULL	
+ALTER TABLE t1 DROP COLUMN b;
+DESC t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	NO		NULL	
+ALTER TABLE t1 MODIFY a BIGINT NOT NULL;
+DESC t1;
+Field	Type	Null	Key	Default	Extra
+a	bigint(20)	NO		NULL	
+ALTER TABLE t1 CHANGE a a INT NOT NULL;
+DESC t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	NO		NULL	
+DROP TABLE t1;
+# ===== csv_alter_table.2 =====
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (a int NOT NULL) ENGINE = CSV;
+ALTER TABLE t1 ADD COLUMN b CHAR(5);
+ERROR 42000: The storage engine for the table doesn't support nullable columns
+DESC t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	NO		NULL	
+ALTER TABLE t1 MODIFY a BIGINT;
+ERROR 42000: The storage engine for the table doesn't support nullable columns
+DESC t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	NO		NULL	
+ALTER TABLE t1 CHANGE a a INT;
+ERROR 42000: The storage engine for the table doesn't support nullable columns
+DESC t1;
+Field	Type	Null	Key	Default	Extra
+a	int(11)	NO		NULL	
+DROP TABLE t1;

=== modified file 'mysql-test/t/disabled.def'
--- a/mysql-test/t/disabled.def	2008-10-15 19:12:49 +0000
+++ b/mysql-test/t/disabled.def	2008-11-05 12:03:55 +0000
@@ -17,7 +17,6 @@ lowercase_table3         : Bug#32667 low
 rpl_log_pos          : Bug#8693 Test 'rpl_log_pos' fails sometimes
 ctype_create         : Bug#32965 main.ctype_create fails
 backup_no_engine     : Bug#36021 2008-04-13 rsomla server crashes when openning table
with unknown storage engine
-csv_alter_table      : Bug#33696 2008-01-21 pcrews no .result file - bug allows NULL
columns in CSV tables
 query_cache_wlock_invalidate_func: Bug#35390 causes not deterministic results.
 cast                 : Bug#35594 2008-03-27 main.cast fails on Windows2003-64
 maria-preload        : Bug#35107 crashes

=== modified file 'storage/csv/ha_tina.cc'
--- a/storage/csv/ha_tina.cc	2008-08-23 00:18:35 +0000
+++ b/storage/csv/ha_tina.cc	2008-11-05 12:03:55 +0000
@@ -1595,10 +1595,21 @@ int ha_tina::check(THD* thd, HA_CHECK_OP
 }
 
 
+/**
+   Return the compatiblity of alter table changes, created for new 
+   fast on-line alter table operation.
+   @param    info                Information about  new altered table properties
+   @param    table_changes       Information if the table layout is changed
+   @retval   COMPATIBLE_DATA_NO  Altered table changes made are incompatible
+   @retval   COMPATIBLE_DATA_YES Altered table changes made are compatible
+*/
 bool ha_tina::check_if_incompatible_data(HA_CREATE_INFO *info,
 					   uint table_changes)
 {
-  return COMPATIBLE_DATA_YES;
+  if (table_changes == IS_EQUAL_NO)  
+    return COMPATIBLE_DATA_NO;
+  else
+    return COMPATIBLE_DATA_YES;    
 }
 
 struct st_mysql_storage_engine csv_storage_engine=