diff --git a/internal-packages/clickhouse/schema/038_add_task_events_inserted_at_index.sql b/internal-packages/clickhouse/schema/038_add_task_events_inserted_at_index.sql
new file mode 100644
index 0000000000..b9e756b2da
--- /dev/null
+++ b/internal-packages/clickhouse/schema/038_add_task_events_inserted_at_index.sql
@@ -0,0 +1,9 @@
+-- +goose Up
+-- Source index supporting closed projector windows on newly written parts.
+-- ADD INDEX only defines the index for new parts and does not materialize existing parts.
+ALTER TABLE trigger_dev.task_events_v2
+  ADD INDEX IF NOT EXISTS idx_inserted_at_projector inserted_at TYPE minmax GRANULARITY 1;
+
+-- +goose Down
+ALTER TABLE trigger_dev.task_events_v2
+  DROP INDEX IF EXISTS idx_inserted_at_projector;