diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 24704b6a023..8d7ef91785e 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -649,7 +649,7 @@ pg_truncate(const char *path, off_t length)
 	fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
 	if (fd >= 0)
 	{
-		ret = ftruncate(fd, 0);
+		ret = ftruncate(fd, length);
 		save_errno = errno;
 		CloseTransientFile(fd);
 		errno = save_errno;