1589994 - Use in-memory rebasing in Mercurial

Status: RESOLVED FIXED

(Conduit :: moz-phab, defect, P2)

Description

[:glob ✱]

moz-phab should use in-memory rebasing for its rebasing work when Mercurial 4.5 or higher is used.

A new experimental config option (rebase.experimental.inmemory=true)
enables rebases to be performed in-memory. Historically, Mercurial (and
Git) touch the working directory when doing history rewriting. On large
repositories or for rebases when the working directory and changesets in
the rebase have many changes, this can make rebase very slow. In-memory
rebasing removes a lot of that overhead.

I did some quick testing with mozilla-central and saw the time for some operations consistently drop from ~250 seconds down to ~30 seconds.

Comment 1

[:glob ✱]

Attachment: Bug 1589994 - use in-memory rebasing; r=zalun

Comment 2

[:glob ✱]

https://github.com/mozilla-conduit/review/commit/7e75288d093fafb583cc5b0ae5d9801186cc284c