Mercurial > public > mercurial-scm > hg-stable
diff mercurial/help/config.txt @ 41823:f6eff9e4de80
storage: introduce a `revlog.reuse-external-delta-parent` config
As pointed in c59987ab96b4, we had no simple way to get a client to not blindly
reuse the delta parent from a bundle. Instead one had to rely on a side effect
of the deprecated `format.generaldelta` configuration.
We introduce an explicit `revlog.reuse-external-delta-parent` configuration
option (default to True) to control this behavior. If the option is not set,
`format.generaldelta` still control this behavior.
To test the new option, we convert a couple of place where `generaldelta` have
been used for its side effects.
| author | Pierre-Yves David <pierre-yves.david@octobus.net> |
|---|---|
| date | Wed, 27 Feb 2019 10:49:25 +0100 |
| parents | 13a6dd952ffe |
| children | 688fc33e105d |
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--- a/mercurial/help/config.txt Sat Mar 02 09:41:17 2019 +0900 +++ b/mercurial/help/config.txt Wed Feb 27 10:49:25 2019 +0100 @@ -1843,6 +1843,28 @@ Turning this option off can result in large increase of repository size for repository with many merges. +``revlog.reuse-external-delta-parent`` + Control the order in which delta parents are considered when adding new + revisions from an external source. + (typically: apply bundle from `hg pull` or `hg push`). + + New revisions are usually provided as a delta against other revisions. By + default, Mercurial will try to reuse this delta first, therefore using the + same "delta parent" as the source. Directly using delta's from the source + reduces CPU usage and usually speeds up operation. However, in some case, + the source might have sub-optimal delta bases and forcing their reevaluation + is useful. For example, pushes from an old client could have sub-optimal + delta's parent that the server want to optimize. (lack of general delta, bad + parents, choice, lack of sparse-revlog, etc). + + This option is enabled by default. Turning it off will ensure bad delta + parent choices from older client do not propagate to this repository, at + the cost of a small increase in CPU consumption. + + Note: this option only control the order in which delta parents are + considered. Even when disabled, the existing delta from the source will be + reused if the same delta parent is selected. + ``server`` ----------