Merge mysql.com:/home/mydev/mysql-4.0

into mysql.com:/home/mydev/mysql-4.0-bug2688

mysql-test/r/bdb.result

@@ -1190,3 +1190,21 @@ a
 A
 a
 drop table t1;
+create table t1 (
+pk1 varchar(8) not null default '',
+pk2 varchar(4) not null default '',
+key1 int(11) default null,
+key2 int(11) default null,
+primary key  (pk1,pk2),
+key key1 (key1),
+key key2 (key2)) engine=bdb;
+insert into t1 values ('','empt',2,2),  ('a','a--a',2,2),
+('bb','b--b',2,2),  ('ccc','c--c',2,2),  ('dddd','d--d',2,2);
+select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
+pk1	pk2	key1	key2
+	empt	2	2
+a	a--a	2	2
+bb	b--b	2	2
+ccc	c--c	2	2
+dddd	d--d	2	2
+drop table t1;

mysql-test/t/bdb.test

@@ -829,3 +829,21 @@ alter table t1 modify a char(10) binary;
 explain select a from t1;
 select a from t1;
 drop table t1;
+
+#
+# bug#2688 - Wrong index_merge query results for BDB table with variable length primary key
+#
+
+create table t1 (
+  pk1 varchar(8) not null default '',
+  pk2 varchar(4) not null default '',
+  key1 int(11) default null,
+  key2 int(11) default null,
+  primary key  (pk1,pk2),
+  key key1 (key1),
+  key key2 (key2)) engine=bdb;
+insert into t1 values ('','empt',2,2),  ('a','a--a',2,2),
+  ('bb','b--b',2,2),  ('ccc','c--c',2,2),  ('dddd','d--d',2,2);
+select * from t1 force index(key1, key2) where key1 < 3 or key2 < 3;
+drop table t1;
+

sql/ha_berkeley.cc

@@ -1611,13 +1611,44 @@ int ha_berkeley::rnd_pos(byte * buf, byte *pos)
 		       (char*) buf, primary_key, &current_row, (DBT*) 0, 0));
 }
 
+/*
+  Set a reference to the current record in (ref,ref_length).
+
+  SYNOPSIS
+    ha_berkeley::position()
+    record                      The current record buffer
+
+  DESCRIPTION
+    The BDB handler stores the primary key in (ref,ref_length).
+    There is either an explicit primary key, or an implicit (hidden)
+    primary key.
+    During open(), 'ref_length' is calculated as the maximum primary
+    key length. When an actual key is shorter than that, the rest of
+    the buffer must be cleared out. The row cannot be identified, if
+    garbage follows behind the end of the key. There is no length
+    field for the current key, so that the whole ref_length is used
+    for comparison.
+
+  RETURN
+    nothing
+*/
+
 void ha_berkeley::position(const byte *record)
 {
   DBT key;
+  DBUG_ENTER("ha_berkeley::position");
   if (hidden_primary_key)
+  {
+    DBUG_ASSERT(ref_length == BDB_HIDDEN_PRIMARY_KEY_LENGTH);
     memcpy_fixed(ref, (char*) current_ident, BDB_HIDDEN_PRIMARY_KEY_LENGTH);
+  }
   else
+  {
     create_key(&key, primary_key, (char*) ref, record);
+    if (key.size < ref_length)
+      bzero(ref + key.size, ref_length - key.size);
+  }
+  DBUG_VOID_RETURN;
 }