new enum instead of string in proto

common/proto/search.proto

@@ -47,12 +47,18 @@ message ReindexResponse {
   uint64 affected_tables = 2;
 }
 
+enum SearchIndexOperation {
+  SEARCH_INDEX_OPERATION_UNSPECIFIED = 0;
+  SEARCH_INDEX_OPERATION_UPSERT = 1;
+  SEARCH_INDEX_OPERATION_DELETE = 2;
+}
+
 message SearchIndexError {
   int64 job_id = 1;
   string profile_name = 2;
   string table_name = 3;
   int64 row_id = 4;
-  string operation = 5;
+  SearchIndexOperation operation = 5;
   int32 attempts = 6;
   string last_error = 7;
 }