From 8934e4f3cc2bdd6c4a24edd0cc6c96ee2325b0dc Mon Sep 17 00:00:00 2001
From: "istruewing@chilla.local" <>
Date: Tue, 27 Mar 2007 10:49:48 +0200
Subject: [PATCH] Bug#24985 - UTF8 ENUM primary key on MEMORY using BTREE      
       causes incorrect duplicate entries

Keys for BTREE indexes on ENUM and SET columns of MEMORY tables
with character set UTF8 were computed incorrectly. Many
different column values got the same key value.

Apart of possible performance problems, it made unique indexes
of this type unusable because it rejected many different
values as duplicates.

The problem was that multibyte character detection was tried
on the internal numeric column value. Many values were not
identified as characters. Their key value became blank filled.

Thanks to Alexander Barkov and Ramil Kalimullin for the patch,
which sets the character set of ENUM and SET key segments to
the pseudo binary character set.
---
 mysql-test/r/heap_btree.result | 12 ++++++++++++
 mysql-test/t/heap_btree.test   | 17 +++++++++++++++++
 sql/ha_heap.cc                 |  5 ++++-
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/heap_btree.result b/mysql-test/r/heap_btree.result
index e6492e90b80..512a8a52845 100644
--- a/mysql-test/r/heap_btree.result
+++ b/mysql-test/r/heap_btree.result
@@ -280,4 +280,16 @@ a
 1
 1
 drop table t1;
+CREATE TABLE t1 (
+c1 ENUM('1', '2'),
+UNIQUE USING BTREE(c1)
+) ENGINE= MEMORY DEFAULT CHARSET= utf8;
+INSERT INTO t1 VALUES('1'), ('2');
+DROP TABLE t1;
+CREATE TABLE t1 (
+c1 SET('1', '2'),
+UNIQUE USING BTREE(c1)
+) ENGINE= MEMORY DEFAULT CHARSET= utf8;
+INSERT INTO t1 VALUES('1'), ('2');
+DROP TABLE t1;
 End of 4.1 tests
diff --git a/mysql-test/t/heap_btree.test b/mysql-test/t/heap_btree.test
index 9aa820becd9..eb4672473f6 100644
--- a/mysql-test/t/heap_btree.test
+++ b/mysql-test/t/heap_btree.test
@@ -182,4 +182,21 @@ delete from t1 where a >= 2;
 select a from t1 order by a;
 drop table t1;
 
+#
+# Bug#24985 - UTF8 ENUM primary key on MEMORY using BTREE
+#             causes incorrect duplicate entries
+#
+CREATE TABLE t1 (
+  c1 ENUM('1', '2'),
+  UNIQUE USING BTREE(c1)
+) ENGINE= MEMORY DEFAULT CHARSET= utf8;
+INSERT INTO t1 VALUES('1'), ('2');
+DROP TABLE t1;
+CREATE TABLE t1 (
+  c1 SET('1', '2'),
+  UNIQUE USING BTREE(c1)
+) ENGINE= MEMORY DEFAULT CHARSET= utf8;
+INSERT INTO t1 VALUES('1'), ('2');
+DROP TABLE t1;
+
 --echo End of 4.1 tests
diff --git a/sql/ha_heap.cc b/sql/ha_heap.cc
index 3e981087df7..dd3a84aaaee 100644
--- a/sql/ha_heap.cc
+++ b/sql/ha_heap.cc
@@ -549,7 +549,10 @@ int ha_heap::create(const char *name, TABLE *table_arg,
       seg->start=   (uint) key_part->offset;
       seg->length=  (uint) key_part->length;
       seg->flag =   0;
-      seg->charset= field->charset();
+      if (field->flags & (ENUM_FLAG | SET_FLAG))
+        seg->charset= &my_charset_bin;
+      else
+        seg->charset= field->charset();
       if (field->null_ptr)
       {
 	seg->null_bit= field->null_bit;