make index column label and options RLocks

index.go

@@ -129,12 +129,26 @@ func (i *Index) SetColumnLabel(v string) error {
 
 // ColumnLabel returns the column label.
 func (i *Index) ColumnLabel() string {
-	i.mu.Lock()
+	i.mu.RLock()
 	v := i.columnLabel
-	i.mu.Unlock()
+	i.mu.RUnlock()
 	return v
 }
 
+// Options returns all options for this index.
+func (i *Index) Options() IndexOptions {
+	i.mu.RLock()
+	defer i.mu.RUnlock()
+	return i.options()
+}
+
+func (i *Index) options() IndexOptions {
+	return IndexOptions{
+		ColumnLabel: i.columnLabel,
+		TimeQuantum: i.timeQuantum,
+	}
+}
+
 // Open opens and initializes the index.
 func (i *Index) Open() error {
 	// Ensure the path exists.