Re: [PATCH] fast-import: Stream very large blobs directly to pack

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 29, 2010, 05:29 UTC
Message-ID: <7vockdjx6w.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20100129012350.GD20488@spearce.org>

"Shawn O. Pearce" <spearce@spearce.org> writes:

> +static void stream_blob(
> +	uintmax_t len,
> +	unsigned char *sha1out,
> +	uintmax_t mark)

A funny way to indent and line wrap...

Show 6 quoted lines

> +{
> + ...
> +	/* Determine if we should auto-checkpoint. */
> +	if ((pack_size + 60 + len) > max_packsize
> +		|| (pack_size + 60 + len) < pack_size)
> +		cycle_packfile();

What's "60" in this math?

If the data is not compressible, we could even grow and the end result might be more than (pack_size + len), busting max_packsize. As we are streaming out, we cannot say "oops, let me try again after truncating and closing the current file and then opening a new file", and instead may have to copy the data from the current one to a new one, and truncate the current one. Is this something worth worrying about?