Google Announces Git protocol version 2, Bringing Significant Performance Improvements

Google today announced the release of Git protocol version 2 (Git protocol version 2) as a major update to the wire protocol of the distributed version control system Git. Version 2 of the Git protocol is more efficient and has significant performance advantages.

The new Git-line protocol provides service-side filtering for references, easy-to-expand features for new features, and client-side processing that simplifies HTTP transmission.

Git protocol version 2

Image: SlideShare

Google has used the new version of the Git protocol internally to increase speed. Brandon Williams of Google’s Git team explained: “We recently rolled out support for protocol version 2 at Google and have seen a performance improvement of 3x for no-op fetches of a single branch on repositories containing 500k references. Protocol v2 has also enabled a reduction of 8x of the overhead bytes (non-packfile) sent from servers. A majority of this improvement is due to filtering references advertised by the server to the refs the client has expressed interest in.

The development of Git protocol-v2 has merged into the mainline of Git 2.18 less than two weeks ago. With significant advantages, Google has supported this new protocol on Git servers in Google Source and Cloud Source repositories.