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7 robbat2 1.4 <meta name="generator" content="Docutils 0.6: http://docutils.sourceforge.net/" />
8 cardoe 1.1 <title>GLEP 61 -- Manifest2 compression</title>
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18     [<b><a href="http://www.gentoo.org/">Gentoo Linux Home</a></b>]
19     [<b><a href="http://www.gentoo.org/proj/en/glep">GLEP Index</a></b>]
20     [<b><a href="http://www.gentoo.org/proj/en/glep/glep-0061.txt">GLEP Source</a></b>]
21     </td></tr></table>
22     <table class="rfc2822 docutils field-list" frame="void" rules="none">
23     <col class="field-name" />
24     <col class="field-body" />
25     <tbody valign="top">
26     <tr class="field"><th class="field-name">GLEP:</th><td class="field-body">61</td>
27     </tr>
28     <tr class="field"><th class="field-name">Title:</th><td class="field-body">Manifest2 compression</td>
29     </tr>
30 robbat2 1.5 <tr class="field"><th class="field-name">Version:</th><td class="field-body">1.5</td>
31 cardoe 1.1 </tr>
32 robbat2 1.5 <tr class="field"><th class="field-name">Last-Modified:</th><td class="field-body"><a class="reference external" href="http://www.gentoo.org/cgi-bin/viewcvs.cgi/xml/htdocs/proj/en/glep/glep-0061.txt?cvsroot=gentoo">2010/01/31 08:27:05</a></td>
33 cardoe 1.1 </tr>
34     <tr class="field"><th class="field-name">Author:</th><td class="field-body">Robin Hugh Johnson &lt;robbat2&#32;&#97;t&#32;gentoo.org&gt;</td>
35     </tr>
36     <tr class="field"><th class="field-name">Status:</th><td class="field-body">Draft</td>
37     </tr>
38     <tr class="field"><th class="field-name">Type:</th><td class="field-body">Standards Track</td>
39     </tr>
40     <tr class="field"><th class="field-name">Content-Type:</th><td class="field-body"><a class="reference external" href="glep-0002.html">text/x-rst</a></td>
41     </tr>
42     <tr class="field"><th class="field-name">Requires:</th><td class="field-body"><a class="reference external" href="http://www.gentoo.org/proj/en/glepglep-0044.html">44</a></td>
43     </tr>
44     <tr class="field"><th class="field-name">Created:</th><td class="field-body">July 2008</td>
45     </tr>
46 robbat2 1.4 <tr class="field"><th class="field-name">Updated:</th><td class="field-body">October 2008, January 2010</td>
47 robbat2 1.3 </tr>
48 cardoe 1.1 <tr class="field"><th class="field-name">Updates:</th><td class="field-body">44</td>
49     </tr>
50 robbat2 1.5 <tr class="field"><th class="field-name">Post-History:</th><td class="field-body">December 2009, January 2010</td>
51 robbat2 1.3 </tr>
52 cardoe 1.1 </tbody>
53     </table>
54     <hr />
55     <div class="contents topic" id="contents">
56     <p class="topic-title first">Contents</p>
57     <ul class="simple">
58     <li><a class="reference internal" href="#abstract" id="id1">Abstract</a></li>
59     <li><a class="reference internal" href="#motivation" id="id2">Motivation</a></li>
60 robbat2 1.5 <li><a class="reference internal" href="#specification" id="id3">Specification</a><ul>
61     <li><a class="reference internal" href="#creation-of-compressed-manifests" id="id4">Creation of compressed Manifests:</a></li>
62     <li><a class="reference internal" href="#validation-of-manifests" id="id5">Validation of Manifests:</a></li>
63     </ul>
64     </li>
65     <li><a class="reference internal" href="#example-results-with-a-32kib-cut-off-gzip-algorithm" id="id6">Example Results with a 32KiB cut-off, gzip algorithm</a></li>
66     <li><a class="reference internal" href="#backwards-compatibility" id="id7">Backwards Compatibility</a></li>
67     <li><a class="reference internal" href="#references" id="id8">References</a></li>
68     <li><a class="reference internal" href="#copyright" id="id9">Copyright</a></li>
69 cardoe 1.1 </ul>
70     </div>
71     <div class="section" id="abstract">
72     <h1><a class="toc-backref" href="#id1">Abstract</a></h1>
73     <p>Deals with compression of large Manifest2 files.</p>
74     </div>
75     <div class="section" id="motivation">
76     <h1><a class="toc-backref" href="#id2">Motivation</a></h1>
77     <p>With the introduction of MetaManifest, and full-tree Manifest coverage,
78     we are faced with the possibility of having very large Manifests.</p>
79     <p>Preliminary experiments with MetaManifest, show that with just the
80 robbat2 1.5 existing per-package Manifests, the full MetaManifest (top-level only,
81     no first-level sub directories), for a tree including metadata/, exceeds
82     8MiB in size. Applying common compression can achieve a 50-60% reduction
83     in this size.</p>
84     <p>Additionally, some of the larger already-existing Manifests in the tree
85     can also be reduced.</p>
86 cardoe 1.1 </div>
87     <div class="section" id="specification">
88     <h1><a class="toc-backref" href="#id3">Specification</a></h1>
89 robbat2 1.5 <div class="section" id="creation-of-compressed-manifests">
90     <h2><a class="toc-backref" href="#id4">Creation of compressed Manifests:</a></h2>
91     <p>32KiB is suggested as a arbitrary cut-off point to start generating
92     compressed Manifest2 files.</p>
93     <p>The compression must only applied during the creation of a tree intended
94     for end users. No Manifests stored in a VCS should be compressed in the
95     VCS. For the main gentoo-portage tree, this means that the compressed
96     Manifests should be generated using the CVS to Rsync process.</p>
97     <p>The Manifest compression process is required to ensure that inconsistent
98     compressed versions do not exist.</p>
99     </div>
100     <div class="section" id="validation-of-manifests">
101     <h2><a class="toc-backref" href="#id5">Validation of Manifests:</a></h2>
102 cardoe 1.1 <p>When searching for a Manifest2 file, if the basename form does not
103     exist, the package manager should search in the same location using
104     common compressed suffixes, and use the compressed file in place of the
105     Manifest2.</p>
106 robbat2 1.4 <p>gzip, bzip2, lzma, xz should all be supported if available on the given
107 cardoe 1.1 platform. In the case that multiple versions exist, the package manager
108     should simply pick one - they should be identical, differing only in
109     compression.</p>
110 robbat2 1.5 </div>
111     </div>
112     <div class="section" id="example-results-with-a-32kib-cut-off-gzip-algorithm">
113     <h1><a class="toc-backref" href="#id6">Example Results with a 32KiB cut-off, gzip algorithm</a></h1>
114     <p>As of 2010/01/30, the suggested cut-off would impact the following 21 existing
115     Manifests, for a saving of nearly 900KiB:</p>
116     <pre class="literal-block">
117     Size Path
118     65788 app-doc/linux-gazette/Manifest
119     75739 app-office/openoffice-bin/Manifest
120     40534 app-text/texlive-core/Manifest
121     41710 dev-texlive/texlive-bibtexextra/Manifest
122     38197 dev-texlive/texlive-documentation-english/Manifest
123     129610 dev-texlive/texlive-fontsextra/Manifest
124     36022 dev-texlive/texlive-humanities/Manifest
125     686118 dev-texlive/texlive-latexextra/Manifest
126     43392 dev-texlive/texlive-latexrecommended/Manifest
127     33375 dev-texlive/texlive-mathextra/Manifest
128     39781 dev-texlive/texlive-pictures/Manifest
129     69567 dev-texlive/texlive-pstricks/Manifest
130     75460 dev-texlive/texlive-publishers/Manifest
131     50879 dev-texlive/texlive-science/Manifest
132     36711 kde-base/kde-l10n/Manifest
133     36539 media-gfx/bootsplash-themes/Manifest
134     33058 net-fs/autofs/Manifest
135     39781 www-client/firefox-bin/Manifest
136     48983 www-client/icecat/Manifest
137     60213 www-client/mozilla-firefox/Manifest
138     39065 x11-themes/gkrellm-themes/Manifest
139     </pre>
140     <p>Additionally, with the MetaManifest proposal, the following new manifests would
141     also be compressed, for a saving of nearly 4MiB:</p>
142     <pre class="literal-block">
143     Size Path
144     33442 app-admin/Manifest
145     71073 app-dicts/Manifest
146     35923 app-emacs/Manifest
147     45808 app-misc/Manifest
148     50169 app-text/Manifest
149     112786 dev-java/Manifest
150     65581 dev-libs/Manifest
151     42619 dev-lisp/Manifest
152     182163 dev-perl/Manifest
153     96198 dev-python/Manifest
154     58963 dev-ruby/Manifest
155     59736 dev-util/Manifest
156     58338 eclass/Manifest
157     55749 kde-base/Manifest
158     110064 licenses/Manifest
159     35262 media-gfx/Manifest
160     53995 media-libs/Manifest
161     55607 media-plugins/Manifest
162     71911 media-sound/Manifest
163     34835 media-video/Manifest
164     5747849 metadata/Manifest
165     47452 net-analyzer/Manifest
166     65989 net-misc/Manifest
167     316787 profiles/Manifest
168     67784 sys-apps/Manifest
169     48971 x11-misc/Manifest
170     41475 x11-plugins/Manifest
171     </pre>
172 cardoe 1.1 </div>
173     <div class="section" id="backwards-compatibility">
174 robbat2 1.5 <h1><a class="toc-backref" href="#id7">Backwards Compatibility</a></h1>
175 cardoe 1.1 <p>The package Manifests should also be maintained as ONLY uncompressed in
176     CVS.</p>
177     <p>For processing of all existing per-package Manifests, if compression is
178     used, it should be done in parallel to the existing Manifests, to
179     provide for a changeover period. Newer versions of Portage may later
180     choose to exclude all non-compressed Manifests during emerge --sync if
181     compressed versions are guaranteed to exist on the servers.</p>
182     <p>MetaManifests may come into existence as compressed from the start, as
183     do not have an backwards compatibility issues.</p>
184     <p>As a side note, this breaks all manual interaction with Manifests
185     such as grep, and so should only be applied to large Manifest2 files,
186 robbat2 1.5 such as the MetaManifest.</p>
187 cardoe 1.1 </div>
188     <div class="section" id="references">
189 robbat2 1.5 <h1><a class="toc-backref" href="#id8">References</a></h1>
190 cardoe 1.1 <table class="docutils footnote" frame="void" id="glep44" rules="none">
191     <colgroup><col class="label" /><col /></colgroup>
192     <tbody valign="top">
193     <tr><td class="label">[1]</td><td>Mauch, M. (2005) GLEP44 - Manifest2 format.
194     <a class="reference external" href="http://www.gentoo.org/proj/en/glep/glep-0044.html">http://www.gentoo.org/proj/en/glep/glep-0044.html</a></td></tr>
195     </tbody>
196     </table>
197     </div>
198     <div class="section" id="copyright">
199 robbat2 1.5 <h1><a class="toc-backref" href="#id9">Copyright</a></h1>
200 robbat2 1.4 <p>Copyright (c) 2008-2010 by Robin Hugh Johnson. This material may be
201 cardoe 1.1 distributed only subject to the terms and conditions set forth in the
202     Open Publication License, v1.0.</p>
203     <p>vim: tw=72 ts=2 expandtab:</p>
204     </div>
205    
206     </div>
207     <div class="footer">
208     <hr class="footer" />
209     <a class="reference external" href="glep-0061.txt">View document source</a>.
210 robbat2 1.5 Generated on: 2010-01-31 08:27 UTC.
211 cardoe 1.1 Generated by <a class="reference external" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference external" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
212    
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