Fix for the bug #971: ORDER BY DESC doesn't return correct num of rows with...

Fix for the bug #971: ORDER BY DESC doesn't return correct num of rows with BDB and an indexed column.

mysql-test/r/bdb.result

@@ -1123,3 +1123,34 @@ a	b
 select * from t2;
 a	b
 drop table t1,t2;
+create table t1  (x int not null, index(x)) type=bdb;
+insert into t1 values (1), (2), (3), (4), (5), (6), (7), (8), (9), (10);
+select * from t1 where x <= 10 and x >= 7;
+x
+7
+8
+9
+10
+select * from t1 where x <= 10 and x >= 7 order by x;
+x
+7
+8
+9
+10
+select * from t1 where x <= 10 and x >= 7 order by x desc;
+x
+10
+9
+8
+7
+select * from t1 where x <= 8 and x >= 5 order by x desc;
+x
+8
+7
+6
+5
+select * from t1 where x < 8 and x > 5 order by x desc;
+x
+7
+6
+drop table t1;

mysql-test/t/bdb.test

@@ -783,3 +783,16 @@ select * from t1;
 select * from t2;
 select * from t2;
 drop table t1,t2;
+
+#
+# The bug #971
+#
+
+create table t1  (x int not null, index(x)) type=bdb;
+insert into t1 values (1), (2), (3), (4), (5), (6), (7), (8), (9), (10);
+select * from t1 where x <= 10 and x >= 7;
+select * from t1 where x <= 10 and x >= 7 order by x;
+select * from t1 where x <= 10 and x >= 7 order by x desc;
+select * from t1 where x <= 8 and x >= 5 order by x desc;
+select * from t1 where x < 8 and x > 5 order by x desc;
+drop table t1;

sql/ha_berkeley.cc

@@ -1420,6 +1420,8 @@ int ha_berkeley::index_read(byte * buf, const byte * key,
   bzero((char*) &row,sizeof(row));
   if (key_len == key_info->key_length)
   {
+    if (find_flag == HA_READ_AFTER_KEY)
+      key_info->handler.bdb_return_if_eq= 1;
     error=read_row(cursor->c_get(cursor, pack_key(&last_key,
 						  active_index,
 						  key_buff,
@@ -1428,6 +1430,7 @@ int ha_berkeley::index_read(byte * buf, const byte * key,
 				 (find_flag == HA_READ_KEY_EXACT ?
 				  DB_SET : DB_SET_RANGE)),
 		   (char*) buf, active_index, &row, (DBT*) 0, 0);
+    key_info->handler.bdb_return_if_eq= 0;
   }
   else
   {