diff --git a/src/ivfutils.c b/src/ivfutils.c
index 2ba6a4e..95f6617 100644
--- a/src/ivfutils.c
+++ b/src/ivfutils.c
@@ -121,7 +121,7 @@ void
 IvfflatCheckMemoryUsage(Size totalSize)
 {
 	/* Add one to error message to ceil */
-	if (totalSize / 1024 > maintenance_work_mem)
+	if (totalSize / 1024 > (Size) maintenance_work_mem)
 		ereport(ERROR,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 				 errmsg("memory required is %zu MB, maintenance_work_mem is %d MB",