commit | f5c89c1a6f01aee6295717fb785a4bfbacb8ce86 | [log] [tgz] |
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author | Patrick Hiesel <hiesel@google.com> | Wed Jan 09 13:45:52 2019 +0100 |
committer | Patrick Hiesel <hiesel@google.com> | Thu Jan 10 16:25:31 2019 +0100 |
tree | 7ad9f05775ccf0d9b0a384278eac029c6a698d2e | |
parent | 572f4e3804bd870ed2a4727b161ae47bae5d15ee [diff] |
Rework SearchingChangeCacheImpl When filtering refs, we previously had two mechanisms for getting change information somewhat efficiently. If the instance is running as a master, we used SearchingChangeCacheImpl to get all change information from the change index. We parsed this and used if for permission filtering. In slaves, we scanned the repo and parsed the changes from disk. There are two reasons for this: (1) we don't have a change index available in slaves. (2) There was no cross-machine eviction. In the master, SearchingChangeCacheImpl was disabled by default, so without manual configuration, we issued one index call for each list-refs call. In addition, we accepted potential staleness of the index. If a change was moved (= the target branch changed) or marked as private and we missed the change index update, it would still be available in Git. This commit reworks the way how we retrieve and store change data for ref filtering: We remove SearchingChangeCacheImpl and replace it with ChangeRefCache. ChangeRefCache has a different caching mechanism. The key contains project, changeId and the SHA1 of the meta ref. This makes it so that we can spare any custom eviction logic and have the Guava cache do it's internal eviction purely based on cache size. This makes the cache suitable for Gerrit slaves as well. In addition, we adapt the way how we load change information: If the change index is available, we bootstrap the cache once per JVM for each project using the index. All subsequent updates are done incrementally using the persisted ChangeNotesCache. This drastically cuts down on the number of index calls we do (one per project per instance vs one per request) while not sacrificing on the benefits. Due to the (comparably) low number of change updates per instance and the (comparably) high number of list ref calls, we will do a very small amount of incremental updates of the cache for any given list ref call. For slaves that don't have a change index available, we don't do any bootstrapping for now and will use the ChangeNotesCache as requests come in. In case this is too slow, we can easily bootstrap the cache in a slave using a lifecycle listener. This will be added in the future if there is a need. Why do we need this cache at all now that we have a ChangeNotesCache? To efficiently filter change refs, all (or nearly all) of the information needs to be in-memory. The ChangeNotesCache is rather large and on googlesource.com we can't hold all of it in memory. ChangeRefCache has a small enough footprint that we can. This might very well be true for other Gerrit instances as well. In case it is not, administrators can choose to disable ChangeRefCache and have their ref filtering be backed by ChangeNotesCache. With this commit, we add integration tests for the new cache and remove complexity from DefaultRefFilter. Change-Id: I5eda9d411e97925e3e8b450fe32693a936164f96
Gerrit is a code review and project management tool for Git based projects.
Gerrit makes reviews easier by showing changes in a side-by-side display, and allowing inline comments to be added by any reviewer.
Gerrit simplifies Git based project maintainership by permitting any authorized user to submit changes to the master Git repository, rather than requiring all approved changes to be merged in by hand by the project maintainer.
For information about how to install and use Gerrit, refer to the documentation.
Our canonical Git repository is located on googlesource.com. There is a mirror of the repository on Github.
Please report bugs on the issue tracker.
Gerrit is the work of hundreds of contributors. We appreciate your help!
Please read the contribution guidelines.
Note that we do not accept Pull Requests via the Github mirror.
The IRC channel on freenode is #gerrit. An archive is available at: echelog.com.
The Developer Mailing list is repo-discuss on Google Groups.
Gerrit is provided under the Apache License 2.0.
Install Bazel and run the following:
git clone --recurse-submodules https://gerrit.googlesource.com/gerrit cd gerrit && bazel build release
The instruction how to configure GerritForge/BinTray repositories is here
On Debian/Ubuntu run:
apt-get update & apt-get install gerrit=<version>-<release>
NOTE: release is a counter that starts with 1 and indicates the number of packages that have been released with the same version of the software.
On CentOS/RedHat run:
yum clean all && yum install gerrit-<version>[-<release>]
On Fedora run:
dnf clean all && dnf install gerrit-<version>[-<release>]
Docker images of Gerrit are available on DockerHub
To run a CentOS 7 based Gerrit image:
docker run -p 8080:8080 gerritforge/gerrit-centos7[:version]
To run a Ubuntu 15.04 based Gerrit image:
docker run -p 8080:8080 gerritforge/gerrit-ubuntu15.04[:version]
NOTE: release is optional. Last released package of the version is installed if the release number is omitted.