Simon Sapin <simon.sapin@octobus.net> [Thu, 15 Jul 2021 23:02:17 +0200] rev 47682
dirstate-v2: Move fixed-size tree metadata into the docket file
Before this changeset, the dirstate-v2 data file contained not only nodes
and paths that may be reused when appending to an existing file,
but also some fixed-size metadata that applies to the entire tree
and was added at the end of the data file for every append.
This moves that metadata into the docket file, so that repeated "append"
operations without meaningful changes don’t actually need to grow any file.
Differential Revision: https://phab.mercurial-scm.org/D11098
Simon Sapin <simon.sapin@octobus.net> [Thu, 08 Jul 2021 19:23:44 +0200] rev 47681
dirstate-v2: Add heuristic for when to create a new data file
… instead of appending to the existing one. This is based on keeping track
of how much of the existing data is not used anymore.
Differential Revision: https://phab.mercurial-scm.org/D11097
Simon Sapin <simon.sapin@octobus.net> [Thu, 15 Jul 2021 10:31:43 +0200] rev 47680
dirstate-v2: Reuse existing paths when appending to a data file
When writing a dirstate in v2 format by appending to an existing data file,
filenames / paths that are borrowed from the previous on-disk representation
can be reused.
Differential Revision: https://phab.mercurial-scm.org/D11096
Simon Sapin <simon.sapin@octobus.net> [Thu, 15 Jul 2021 08:53:03 +0200] rev 47679
dirstate-v2: Reuse existing nodes when appending to a data file
When writing a dirstate in v2 format by appending to an existing data file,
nodes that are still "unparsed" from the previous on-disk representation
have been unchanged and can therefore be reused.
This makes the new data point to previously-existing data for tree nodes.
Differential Revision: https://phab.mercurial-scm.org/D11095
Simon Sapin <simon.sapin@octobus.net> [Tue, 13 Jul 2021 17:18:23 +0200] rev 47678
dirstate-v2: Support appending to the same data file
For now we’re still writing the entire data every time, so appending is not
useful yet. Later we’ll have new nodes pointing to some existing data for
nodes and paths that haven’t changed.
The decision whether to append is pseudo-random in order to make tests exercise
both code paths. This will be replaced by a heuristic based on the amount
of unused existing data.
Differential Revision: https://phab.mercurial-scm.org/D11094
Simon Sapin <simon.sapin@octobus.net> [Tue, 13 Jul 2021 09:44:44 +0200] rev 47677
dirstate-v2: shrink on-disk path lengths to 16-bits
Differential Revision: https://phab.mercurial-scm.org/D11091