obsolete: order of magnitude speedup in _computebumpedset
Reminder: a changeset is said "bumped" if it tries to obsolete a immutable
changeset.
The previous algorithm for computing bumped changeset was:
1) Get all public changesets
2) Find all they successors
3) Search for stuff that are eligible for being "bumped"
(mutable and non obsolete)
The entry size of this algorithm is `O(len(public))` which is mostly the same as
`O(len(repo))`. Even this this approach mean fewer obsolescence marker are
traveled, this is not very scalable.
The new algorithm is:
1) For each potential bumped changesets (non obsolete mutable)
2) iterate over precursors
3) if a precursors is public. changeset is bumped
We travel more obsolescence marker, but the entry size is much smaller since
the amount of potential bumped should remains mostly stable with time `O(1)`.
On some confidential gigantic repo this move bumped computation from 15.19s to
0.46s (×33 speedup…). On "smaller" repo (mercurial, cubicweb's review) no
significant gain were seen. The additional traversal of obsolescence marker is
probably probably counter balance the advantage of it.
Other optimisation could be done in the future (eg: sharing precursors cache
for divergence detection)
$ "$TESTDIR/hghave" serve || exit 80
Test chains of near empty directories, terminating 3 different ways:
- a1: file at level 4 (deepest)
- b1: two dirs at level 3
- e1: file at level 2
Set up the repo
$ hg init test
$ cd test
$ mkdir -p a1/a2/a3/a4
$ mkdir -p b1/b2/b3/b4
$ mkdir -p b1/b2/c3/c4
$ mkdir -p d1/d2/d3/d4
$ echo foo > a1/a2/a3/a4/foo
$ echo foo > b1/b2/b3/b4/foo
$ echo foo > b1/b2/c3/c4/foo
$ echo foo > d1/d2/d3/d4/foo
$ echo foo > d1/d2/foo
$ hg ci -Ama
adding a1/a2/a3/a4/foo
adding b1/b2/b3/b4/foo
adding b1/b2/c3/c4/foo
adding d1/d2/d3/d4/foo
adding d1/d2/foo
$ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -E errors.log
$ cat hg.pid >> $DAEMON_PIDS
manifest with descending
$ "$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT 'file'
200 Script output follows
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US">
<head>
<link rel="icon" href="/static/hgicon.png" type="image/png" />
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="/static/style-paper.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: 9087c84a0f5d /</title>
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="http://mercurial.selenic.com/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li><a href="/shortlog/9087c84a0f5d">log</a></li>
<li><a href="/graph/9087c84a0f5d">graph</a></li>
<li><a href="/tags">tags</a></li>
<li><a href="/bookmarks">bookmarks</a></li>
<li><a href="/branches">branches</a></li>
</ul>
<ul>
<li><a href="/rev/9087c84a0f5d">changeset</a></li>
<li class="active">browse</li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
</div>
<div class="main">
<h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
<h3>directory / @ 0:9087c84a0f5d <span class="tag">tip</span> </h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" /></p>
<div id="hint">Find changesets by keywords (author, files, the commit message), revision
number or hash, or <a href="/help/revsets">revset expression</a>.</div>
</form>
<table class="bigtable">
<tr>
<th class="name">name</th>
<th class="size">size</th>
<th class="permissions">permissions</th>
</tr>
<tbody class="stripes2">
<tr class="fileline">
<td class="name"><a href="/file/9087c84a0f5d/">[up]</a></td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/9087c84a0f5d/a1">
<img src="/static/coal-folder.png" alt="dir."/> a1/
</a>
<a href="/file/9087c84a0f5d/a1/a2/a3/a4">
a2/a3/a4
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/9087c84a0f5d/b1">
<img src="/static/coal-folder.png" alt="dir."/> b1/
</a>
<a href="/file/9087c84a0f5d/b1/b2">
b2
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/9087c84a0f5d/d1">
<img src="/static/coal-folder.png" alt="dir."/> d1/
</a>
<a href="/file/9087c84a0f5d/d1/d2">
d2
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
</tbody>
</table>
</div>
</div>
<script type="text/javascript">process_dates()</script>
</body>
</html>
$ cat errors.log
$ cd ..