Summary:
Fetching all history of both filenodes to see if there's common history either side of a merge is wasteful, and in some megarepo work is causing long delays deriving merge changesets.
Where we have already derived filenodes for a given merge's ancestors, we can go faster; we can use the linknodes to determine the older of the two filenodes, and fetch only history for the newer of the two.
This is imperfect for the import use case, since filenodes depend on hgchangesets, and the batching in use at the moment prefers to generate all derived data of a given type before moving onto another type, but it's an improvement for cases where some filenodes are already derived (e.g. due to import of a repo with a similar history).
Reviewed By: StanislavGlebik
Differential Revision: D28796253
fbshipit-source-id: 5384b5d2841844794a518c321dbf995891374d3a
Mononoke is a next-generation server for the Mercurial source control
system, meant to scale up to accepting
thousands of commits every hour across millions of files. It is primarily
written in the Rust programming language.
Caveat Emptor
Mononoke is still in early stages of development. We are making it available now because we plan to
start making references to it from our other open source projects.
The version that we provide on GitHub does not build yet.
This is because the code is exported verbatim from an internal repository at Facebook, and
not all of the scaffolding from our internal repository can be easily extracted. The key areas
where we need to shore things up are:
Full support for a standard cargo build.
Open source replacements for Facebook-internal services (blob store, logging etc).
The current goal is to get Mononoke working on Linux. Other Unix-like OSes may
be supported in the future
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