##// END OF EJS Templates
emitrevision: consider ancestors revision to emit as available base...
emitrevision: consider ancestors revision to emit as available base This should make more delta base valid. This notably affects: * case where we skipped some parent with empty delta to directly delta against an ancestors * case where an intermediate snapshots is stored. This change means we could sent largish intermediate snapshots over the wire. However this is actually a sub goal here. Sending snapshots over the wire means the client have a high odd of simply storing the pre-computed delta instead of doing a lengthy process that will… end up doing the same intermediate snapshot. In addition the overall size of snapshot (or any level) is "only" some or the overall delta size. (0.17% for my mercurial clone, 20% for my clone of Mozilla try). So Sending them other the wire is unlikely to change large impact on the bandwidth used. If we decide that minimising the bandwidth is an explicit goal, we should introduce new logic to filter-out snapshot as delta. The current code has no notion explicite of snapshot so far, they just tended to fall into the wobbly filtering options. In some cases, this patch can yield large improvement to the bundling time: ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = perf-bundle # benchmark.variants.revs = last-100000 before: 68.787066 seconds after: 47.552677 seconds (-30.87%) That translate to large improvement to the pull time : ### data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog # benchmark.name = pull # benchmark.variants.issue6528 = disabled # benchmark.variants.revs = last-100000 before: 142.186625 seconds after: 75.897745 seconds (-46.62%) No significant negative impact have been observed.

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evolution.txt
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Obsolescence markers make it possible to mark changesets that have been
deleted or superseded in a new version of the changeset.
Unlike the previous way of handling such changes, by stripping the old
changesets from the repository, obsolescence markers can be propagated
between repositories. This allows for a safe and simple way of exchanging
mutable history and altering it after the fact. Changeset phases are
respected, such that only draft and secret changesets can be altered (see
:hg:`help phases` for details).
Obsolescence is tracked using "obsolescence markers", a piece of metadata
tracking which changesets have been made obsolete, potential successors for
a given changeset, the moment the changeset was marked as obsolete, and the
user who performed the rewriting operation. The markers are stored
separately from standard changeset data can be exchanged without any of the
precursor changesets, preventing unnecessary exchange of obsolescence data.
The complete set of obsolescence markers describes a history of changeset
modifications that is orthogonal to the repository history of file
modifications. This changeset history allows for detection and automatic
resolution of edge cases arising from multiple users rewriting the same part
of history concurrently.
Current feature status
======================
This feature is still in development.
Instability
===========
Rewriting changesets might introduce instability.
There are two main kinds of instability: orphaning and diverging.
Orphans are changesets left behind when their ancestors are rewritten.
Divergence has two variants:
* Content-divergence occurs when independent rewrites of the same changesets
lead to different results.
* Phase-divergence occurs when the old (obsolete) version of a changeset
becomes public.
It is possible to prevent local creation of orphans by using the following config::
[experimental]
evolution.createmarkers = true
evolution.exchange = true
You can also enable that option explicitly::
[experimental]
evolution.createmarkers = true
evolution.exchange = true
evolution.allowunstable = true