Mateusz Kwapich <mitrandir@fb.com> [Thu, 06 Nov 2014 14:20:05 -0800] rev 23255
revlog: add config variable for limiting delta-chain length
The current heuristic for deciding between storing delta and full texts
is based on ratio of (sizeofdeltas)/(sizeoffulltext).
In some cases (for example a manifest for ahuge repo) this approach
can result in extremely long delta chains (~30,000) which are very slow to
read. (In the case of a manifest ~500ms are added to every hg command because of that).
This commit introduces "revlog.maxchainlength" configuration variable that will
limit delta chain length.
Mateusz Kwapich <mitrandir@fb.com> [Thu, 06 Nov 2014 14:08:25 -0800] rev 23254
debugrevlog: fix computing chain length in debugrevlog -d
The chain length was computed correctly only when generaldelta
feature was enabled. Now it's fixed.
When generaldelta is disabled the base revision in revlog index is not
the revision we have delta against - it's always previous revision.
Instead of incorrect chainbaseandlen in command.py we are now using two
single-responsibility functions in revlog.py:
- chainbase(rev)
- chainlen(rev)
Only chainlen(rev) was missing so it was written to mimic the way the
chain of deltas is actually found during file reconstruction.
Pierre-Yves David <pierre-yves.david@fb.com> [Wed, 05 Nov 2014 10:13:01 +0000] rev 23253
transaction: factorise append-only file registration
The addition is done in two different places but differs slightly. We factorise
this addition to ensure it is consistent in all places.
Pierre-Yves David <pierre-yves.david@fb.com> [Wed, 05 Nov 2014 13:00:48 +0000] rev 23252
transaction: document `tr.add`
Pierre-Yves David <pierre-yves.david@fb.com> [Wed, 05 Nov 2014 10:05:38 +0000] rev 23251
transaction: drop backupentries logic from startgroup and endgroup
The `startgroup` and `endgroup` methods are used in a very specific
context to wrap a very specific operation (revlog truncation). It does
not make sense to perform any other operations during such a "group"
(eg:file backup). There is currently no user of backupfile during a
"group" so we drop the group-specific code and restrict authorized
operations during "group".
Pierre-Yves David <pierre-yves.david@fb.com> [Wed, 05 Nov 2014 10:00:15 +0000] rev 23250
transaction: document startgroup and endgroup
These enigmatic methods are only used in repair. We document them to clarify
there purpose and user.