From cb0f1641fe4f746508e7715fa9417c6afa19e9cc Mon Sep 17 00:00:00 2001
From: unknown <mikael@c-0409e253.1238-1-64736c10.cust.bredbandsbolaget.se>
Date: Tue, 13 Jun 2006 22:46:38 -0400
Subject: [PATCH 1/2] BUG#20397: Crash at ALTER TABLE t1 engine = x; for
 partitioned table

mysql-test/r/partition_error.result:
  New test cases
mysql-test/t/partition_error.test:
  New test cases
sql/sql_table.cc:
  ALTER TABLE t1 engine = x;
  will behave exactly like
  ALTER TABLE t1;
  See no reason why one should change handler to something not specified in query when
  there is already something one is attached to.
---
 mysql-test/r/partition_error.result | 24 ++++++++++++++++++++++++
 mysql-test/t/partition_error.test   | 20 ++++++++++++++++++++
 sql/sql_table.cc                    | 12 ++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/mysql-test/r/partition_error.result b/mysql-test/r/partition_error.result
index a7ca3d9b2fa..a4866209ee6 100644
--- a/mysql-test/r/partition_error.result
+++ b/mysql-test/r/partition_error.result
@@ -1,4 +1,28 @@
 drop table if exists t1;
+create table t1 (a int)
+engine = x
+partition by key (a);
+Warnings:
+Error	1286	Unknown table engine 'x'
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 PARTITION BY KEY (a) 
+drop table t1;
+create table t1 (a int)
+engine = innodb
+partition by list (a)
+(partition p0 values in (0));
+alter table t1 engine = x;
+Warnings:
+Error	1286	Unknown table engine 'x'
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) DEFAULT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=latin1 PARTITION BY LIST (a) (PARTITION p0 VALUES IN (0) ENGINE = InnoDB)
+drop table t1;
 partition by list (a)
 partitions 3
 (partition x1 values in (1,2,9,4) tablespace ts1,
diff --git a/mysql-test/t/partition_error.test b/mysql-test/t/partition_error.test
index 659f0b8cef4..39fde685bce 100644
--- a/mysql-test/t/partition_error.test
+++ b/mysql-test/t/partition_error.test
@@ -8,6 +8,24 @@
 drop table if exists t1;
 --enable_warnings
 
+#
+# Bug 20397: Partitions: Crash when using non-existing engine
+#
+create table t1 (a int)
+engine = x
+partition by key (a);
+show create table t1;
+drop table t1;
+
+create table t1 (a int)
+engine = innodb
+partition by list (a)
+(partition p0 values in (0));
+
+alter table t1 engine = x;
+show create table t1;
+drop table t1;
+
 #
 # Partition by key stand-alone error
 #
@@ -775,3 +793,5 @@ partition by range (a + (select count(*) from t1))
 -- error ER_PARTITION_FUNC_NOT_ALLOWED_ERROR
 create table t1 (a char(10))
 partition by hash (extractvalue(a,'a'));
+
+
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index a49b7a2cc42..58d50727000 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -4992,7 +4992,19 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
 
   old_db_type= table->s->db_type;
   if (!create_info->db_type)
+  {
+    if (create_info->used_fields & HA_CREATE_USED_ENGINE)
+    {
+      /*
+        This case happens when the user specified
+        ENGINE = x where x is a non-existing storage engine
+        We clear the flag and treat it the same way
+        as if no storage engine was specified.
+      */
+      create_info->used_fields^= HA_CREATE_USED_ENGINE;
+    }
     create_info->db_type= old_db_type;
+  }
 
 #ifdef WITH_PARTITION_STORAGE_ENGINE
   if (prep_alter_part_table(thd, table, alter_info, create_info, old_db_type,

From 6dd40f3e0ab74846d7793cc32065b4c2aa7741f5 Mon Sep 17 00:00:00 2001
From: unknown <mikael@c-0409e253.1238-1-64736c10.cust.bredbandsbolaget.se>
Date: Thu, 15 Jun 2006 15:56:47 -0400
Subject: [PATCH 2/2] BUG#20397: Crash when alter table t1 engine = x; Review
 fixes

sql/sql_table.cc:
  Review fixes
---
 sql/sql_table.cc | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 58d50727000..7e25c4848ca 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -4993,17 +4993,20 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
   old_db_type= table->s->db_type;
   if (!create_info->db_type)
   {
-    if (create_info->used_fields & HA_CREATE_USED_ENGINE)
+    if (table->part_info &&
+        create_info->used_fields & HA_CREATE_USED_ENGINE)
     {
       /*
         This case happens when the user specified
         ENGINE = x where x is a non-existing storage engine
-        We clear the flag and treat it the same way
-        as if no storage engine was specified.
+        We set create_info->db_type to default_engine_type
+        to ensure we don't change underlying engine type
+        due to a erroneously given engine name.
       */
-      create_info->used_fields^= HA_CREATE_USED_ENGINE;
+      create_info->db_type= table->part_info->default_engine_type;
     }
-    create_info->db_type= old_db_type;
+    else
+      create_info->db_type= old_db_type;
   }
 
 #ifdef WITH_PARTITION_STORAGE_ENGINE