Autogenerated HTML docs for v2.11.0-295-gd7dff
diff --git a/git-gc.html b/git-gc.html index e3f29c0..f5194a2 100644 --- a/git-gc.html +++ b/git-gc.html
@@ -818,11 +818,10 @@ <p> Prune loose objects older than date (default is 2 weeks ago, overridable by the config variable <code>gc.pruneExpire</code>). - --prune=all prunes loose objects regardless of their age (do - not use --prune=all unless you know exactly what you are doing. - Unless the repository is quiescent, you will lose newly created - objects that haven’t been anchored with the refs and end up - corrupting your repository). --prune is on by default. + --prune=all prunes loose objects regardless of their age and + increases the risk of corruption if another process is writing to + the repository concurrently; see "NOTES" below. --prune is on by + default. </p> </dd> <dt class="hdlist1"> @@ -904,15 +903,41 @@ <div class="sect1"> <h2 id="_notes">Notes</h2> <div class="sectionbody"> -<div class="paragraph"><p><em>git gc</em> tries very hard to be safe about the garbage it collects. In +<div class="paragraph"><p><em>git gc</em> tries very hard not to delete objects that are referenced +anywhere in your repository. In particular, it will keep not only objects referenced by your current set of branches and tags, but also objects referenced by the index, remote-tracking branches, refs saved by <em>git filter-branch</em> in refs/original/, or reflogs (which may reference commits in branches -that were later amended or rewound).</p></div> -<div class="paragraph"><p>If you are expecting some objects to be collected and they aren’t, check +that were later amended or rewound). +If you are expecting some objects to be deleted and they aren’t, check all of those locations and decide whether it makes sense in your case to remove those references.</p></div> +<div class="paragraph"><p>On the other hand, when <em>git gc</em> runs concurrently with another process, +there is a risk of it deleting an object that the other process is using +but hasn’t created a reference to. This may just cause the other process +to fail or may corrupt the repository if the other process later adds a +reference to the deleted object. Git has two features that significantly +mitigate this problem:</p></div> +<div class="olist arabic"><ol class="arabic"> +<li> +<p> +Any object with modification time newer than the <code>--prune</code> date is kept, + along with everything reachable from it. +</p> +</li> +<li> +<p> +Most operations that add an object to the database update the + modification time of the object if it is already present so that #1 + applies. +</p> +</li> +</ol></div> +<div class="paragraph"><p>However, these features fall short of a complete solution, so users who +run commands concurrently have to live with some risk of corruption (which +seems to be low in practice) unless they turn off automatic garbage +collection with <em>git config gc.auto 0</em>.</p></div> </div> </div> <div class="sect1"> @@ -941,7 +966,7 @@ <div id="footnotes"><hr /></div> <div id="footer"> <div id="footer-text"> -Last updated 2016-06-27 11:04:05 PDT +Last updated 2017-01-10 15:42:58 PST </div> </div> </body>
