diff --git a/.gitignore b/.gitignore
old mode 100644
new mode 100755
diff --git a/bolt.go b/bolt.go
old mode 100644
new mode 100755
diff --git a/cache.go b/cache.go
old mode 100644
new mode 100755
diff --git a/cli/: b/cli/:
new file mode 100755
index 0000000..e69de29
diff --git a/cli/main.go b/cli/main.go
old mode 100644
new mode 100755
diff --git a/db.go b/db.go
old mode 100644
new mode 100755
diff --git a/db_test.go b/db_test.go
old mode 100644
new mode 100755
index 2e6b028..597b90c
--- a/db_test.go
+++ b/db_test.go
@@ -94,24 +94,6 @@ func TestImplementations(t *testing.T) {
 		cases = append(cases, leveldb)
 	}
 
-	riakLN, err := net.Listen("tcp", "localhost:8087")
-	if err == nil {
-		defer riakLN.Close()
-		go func() {
-			for {
-				conn, err := riakLN.Accept()
-				if err == nil {
-					conn.Close()
-				}
-			}
-		}()
-	}
-	if riak, err := NewRiak("localhost:8087"); err != nil {
-		t.Logf("cannot make riak: %v", err)
-	} else {
-		cases = append(cases, riak)
-	}
-
 	mongoLN, err := net.Listen("tcp", "localhost:27017")
 	if err == nil {
 		defer mongoLN.Close()
diff --git a/dynomite.go b/dynomite.go
old mode 100644
new mode 100755
diff --git a/errors.go b/errors.go
old mode 100644
new mode 100755
diff --git a/leveldb.go b/leveldb.go
old mode 100644
new mode 100755
index 089dfdb..18f26c0
--- a/leveldb.go
+++ b/leveldb.go
@@ -68,8 +68,13 @@ func (ldb *LevelDB) Get(key string, ns ...string) ([]byte, error) {
 
 func (ldb *LevelDB) Set(key string, value []byte, ns ...string) error {
 	namespace := resolveNamespace(ns)
+	key = path.Join(namespace, key)
 	batch := &leveldb.Batch{}
-	batch.Put([]byte(path.Join(namespace, key)), value)
+	if value != nil {
+		batch.Put([]byte(key), value)
+	} else {
+		batch.Delete([]byte(key))
+	}
 	return ldb.db.Write(batch, nil)
 }
 
diff --git a/map.go b/map.go
old mode 100644
new mode 100755
index 297c51d..7338cca
--- a/map.go
+++ b/map.go
@@ -33,10 +33,11 @@ func (m *Map) List(ns []string, limits ...string) ([]string, error) {
 	limits = resolveLimits(limits)
 
 	keys := []string{}
-	if _, ok := (*m)[namespace]; !ok {
-		return nil, nil
+	n, _ := (*m)[DefaultNamespace]
+	if v, ok := (*m)[namespace]; ok {
+		n = v
 	}
-	for k := range (*m)[namespace] {
+	for k := range n {
 		if k >= limits[0] && k <= limits[1] {
 			keys = append(keys, k)
 		}
diff --git a/memcache.go b/memcache.go
old mode 100644
new mode 100755
diff --git a/memcachecluster.go b/memcachecluster.go
old mode 100644
new mode 100755
diff --git a/minio.go b/minio.go
old mode 100644
new mode 100755
diff --git a/mongo.go b/mongo.go
old mode 100644
new mode 100755
diff --git a/redis.go b/redis.go
old mode 100644
new mode 100755
diff --git a/type.go b/type.go
old mode 100644
new mode 100755