diff --git a/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json b/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json
index 58b6b2d3bc873..7a29c549d750a 100644
--- a/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json
+++ b/server/src/main/resources/org/opensearch/tasks/task-index-mapping.json
@@ -34,6 +34,9 @@
           "start_time_in_millis": {
             "type": "long"
           },
+          "cancellation_time_millis": {
+            "type": "long"
+          },
           "type": {
             "type": "keyword"
           },