diff --git a/api.go b/api.go
index 018eb8091..9f4190535 100644
--- a/api.go
+++ b/api.go
@@ -812,6 +812,9 @@ func (api *API) Usage() (map[string]int64, int64, error) {
 		if !file.IsDir() {
 			continue
 		}
+		if api.holder.Txf().IsTxDatabasePath(file.Name()) {
+			continue
+		}
 		fullName := path.Join(dirName, file.Name())
 		indexSizes[file.Name()], err = diskUsage(fullName)
 		if err != nil {
diff --git a/txfactory_internal_test.go b/txfactory_internal_test.go
index dd8225aa7..d172099d5 100644
--- a/txfactory_internal_test.go
+++ b/txfactory_internal_test.go
@@ -95,9 +95,9 @@ func Test_TxFactory_Qcx_query_context(t *testing.T) {
 	// allow all goro to finish before Closing the lmdb.env, otherwise
 	// we will crash as the goroutines making Tx will try to use the env
 	// after it is closed. It can take quite a while.
-	// one writer might be blocking the other... so ask for only N-1 at first.
-	barrier.BlockUntil(N - 1)
-	//barrier.BlockUntil(N)
+	// one writer might be blocking the other... so ask for only N-2 at first
+	// to avoid deadlock.
+	barrier.BlockUntil(N - 2)
 	barrier.UnblockReaders()
 	time.Sleep(1 * time.Second)
 }