Re: upload-pack is slow with lots of refs

> Am 10/3/2012 21:41, schrieb Shawn Pearce:
>> On Wed, Oct 3, 2012 at 11:55 AM, Jeff King <peff@peff.net> wrote:
>>> On Wed, Oct 03, 2012 at 11:53:35AM -0700, Junio C Hamano wrote:
>>>> Jeff King <peff@peff.net> writes:
>>>>
>>>>>> Has there been any work on extending the protocol so that the client
>>>>>> tells the server what refs it's interested in?
>>>>>
>>>>> I don't think so. It would be hard to do in a backwards-compatible way,
>>>>> because the advertisement is the first thing the server says, before it
>>>>> has negotiated any capabilities with the client at all.
>>>>
>>>> That is being discussed but hasn't surfaced on the list.
>>>
>>> Out of curiosity, how are you thinking about triggering such a new
>>> behavior in a backwards-compatible way? Invoke git-upload-pack2, and
>>> fall back to reconnecting to start git-upload-pack if it fails?
>>
>> Basically, yes. New clients connect for git-upload-pack2. Over git://
>> the remote peer will just close the TCP socket with no messages. The
>> client can fallback to git-upload-pack and try again. Over SSH a
>> similar thing will happen in the sense there is no data output from
>> the remote side, so the client can try again.
>
> These connections are bidirectional.

> Upload-pack can just start
> advertising refs in the "v1" way and announce a "v2" capability and listen
> for response in parallel. A v2 capable client can start sending "wants" or
> some other signal as soon as it sees the "v2" capability. Upload-pack,
> which was listening for responses in parallel, can interrupt its
> advertisements and continue with v2 protocol from here.
>
> This sounds so simple (not the implementation, of course) - I must be
> missing something.