add distinct
diff --git a/s2graphql/src/main/scala/org/apache/s2graph/graphql/repository/GraphRepository.scala b/s2graphql/src/main/scala/org/apache/s2graph/graphql/repository/GraphRepository.scala
index bd98504..1bac416 100644
--- a/s2graphql/src/main/scala/org/apache/s2graph/graphql/repository/GraphRepository.scala
+++ b/s2graphql/src/main/scala/org/apache/s2graph/graphql/repository/GraphRepository.scala
@@ -279,7 +279,7 @@
   }
 
   def services(): List[Service] = {
-    Service.findAll()
+    Service.findAll().distinct
   }
 
   def serviceColumns(): List[ServiceColumn] = {
@@ -288,6 +288,7 @@
     ServiceColumn
       .findAll()
       .filter(sc => allServices(sc.service))
+      .distinct
   }
 
   def labels() = {
@@ -296,6 +297,6 @@
     Label
       .findAll()
       .filter(l => allServiceColumns(l.srcColumn) || allServiceColumns(l.tgtColumn))
+      .distinct
   }
-
 }