diff --git a/contrib/basic_archive/basic_archive.c b/contrib/basic_archive/basic_archive.c
index 776a386e35..a02708fc12 100644
--- a/contrib/basic_archive/basic_archive.c
+++ b/contrib/basic_archive/basic_archive.c
@@ -265,7 +265,7 @@ basic_archive_file_internal(const char *file, const char *path)
 	 */
 	gettimeofday(&tv, NULL);
 	if (pg_mul_u64_overflow((uint64) 1000, (uint64) tv.tv_sec, &epoch) ||
-		pg_add_u64_overflow(epoch, (uint64) tv.tv_usec, &epoch))
+		pg_add_u64_overflow(epoch, (uint64) tv.tv_usec / 1000, &epoch))
 		elog(ERROR, "could not generate temporary file name for archiving");
 
 	snprintf(temp, sizeof(temp), "%s/%s.%s.%d." UINT64_FORMAT,