From: Eric Wong Date: Thu, 02 May 2019 08:50:55 GMT Subject: Re: "IMAP IDLE"-like long-polling "git fetch" Message-ID: <20190502085055.34kkll2deowat6il@dcvr> In-Reply-To: Stefan Beller wrote: > IIRC, More than half the bandwidth of Googles git servers are used > for ls-remote calls (i.e. polling a lot of repos, most of them did *not* > change, by build bots which are really eager to try again after a minute). Thinking back at that statement; I think polling can be optimized in git, at least. IIRC, your repos have lots of refs; right? (which is why it's a bandwidth problem) Since info/refs is a static file (hopefully updated by a post-update hook), the smart client can make an HTTP request to check If-Modified-Since: to avoid the big response. The client would need to cache the mtime of the last requested refs file; somewhere. IOW, do refs negotiation the "dumb" way; since it's no better than the smart way, really. Keep doing object transfers the smart way. During the initial clone, smart servers could probably have a header informing clients that their info/refs is up-to-date and clients can do dumb refs negotiation.