diff --git a/src/ivfflat.c b/src/ivfflat.c
index 53314a3..bcf25c7 100644
--- a/src/ivfflat.c
+++ b/src/ivfflat.c
@@ -206,6 +206,9 @@ ivfflathandler(PG_FUNCTION_ARGS)
 	amroutine->ambuildphasename = ivfflatbuildphasename;
 #endif
 	amroutine->amvalidate = ivfflatvalidate;
+#if PG_VERSION_NUM >= 140000
+	amroutine->amadjustmembers = NULL;
+#endif
 	amroutine->ambeginscan = ivfflatbeginscan;
 	amroutine->amrescan = ivfflatrescan;
 	amroutine->amgettuple = ivfflatgettuple;