Yorick Peterse
054f2f98ed
Instead of using MAX(events.updated_at) we can simply sort the events in
descending order by the "id" column and grab the first row. In other
words, instead of this:
SELECT max(events.updated_at) AS max_id
FROM events
LEFT OUTER JOIN projects ON projects.id = events.project_id
LEFT OUTER JOIN namespaces ON namespaces.id = projects.namespace_id
WHERE events.author_id IS NOT NULL
AND events.project_id IN (13083);
we can use this:
SELECT events.updated_at AS max_id
FROM events
LEFT OUTER JOIN projects ON projects.id = events.project_id
LEFT OUTER JOIN namespaces ON namespaces.id = projects.namespace_id
WHERE events.author_id IS NOT NULL
AND events.project_id IN (13083)
ORDER BY events.id DESC
LIMIT 1;
This has the benefit that on PostgreSQL a backwards index scan can be
used, which due to the "LIMIT 1" will at most process only a single row.
This in turn greatly speeds up the process of grabbing the latest update
time. This can be confirmed by looking at the query plans. The first
query produces the following plan:
Aggregate (cost=43779.84..43779.85 rows=1 width=12) (actual time=2142.462..2142.462 rows=1 loops=1)
-> Index Scan using index_events_on_project_id on events (cost=0.43..43704.69 rows=30060 width=12) (actual time=0.033..2138.086 rows=32769 loops=1)
Index Cond: (project_id = 13083)
Filter: (author_id IS NOT NULL)
Planning time: 1.248 ms
Execution time: 2142.548 ms
The second query in turn produces the following plan:
Limit (cost=0.43..41.65 rows=1 width=16) (actual time=1.394..1.394 rows=1 loops=1)
-> Index Scan Backward using events_pkey on events (cost=0.43..1238907.96 rows=30060 width=16) (actual time=1.394..1.394 rows=1 loops=1)
Filter: ((author_id IS NOT NULL) AND (project_id = 13083))
Rows Removed by Filter: 2104
Planning time: 0.166 ms
Execution time: 1.408 ms
According to the above plans the 2nd query is around 1500 times faster.
However, re-running the first query produces timings of around 80 ms,
making the 2nd query "only" around 55 times faster.
GitLab
Canonical source
The source of GitLab Community Edition is hosted on GitLab.com and there are mirrors to make contributing as easy as possible.
Open source software to collaborate on code
To see how GitLab looks please see the features page on our website.
- Manage Git repositories with fine grained access controls that keep your code secure
- Perform code reviews and enhance collaboration with merge requests
- Each project can also have an issue tracker and a wiki
- Used by more than 100,000 organizations, GitLab is the most popular solution to manage Git repositories on-premises
- Completely free and open source (MIT Expat license)
- Powered by Ruby on Rails
Editions
There are two editions of GitLab:
- GitLab Community Edition (CE) is available freely under the MIT Expat license.
- GitLab Enterprise Edition (EE) includes extra features that are more useful for organizations with more than 100 users. To use EE and get official support please become a subscriber.
Included with the GitLab Omnibus Packages is GitLab CI that can easily build, test and deploy code.
Website
On about.gitlab.com you can find more information about:
- Subscriptions
- Consultancy
- Community
- Hosted GitLab.com use GitLab as a free service
- GitLab Enterprise Edition with additional features aimed at larger organizations.
- GitLab CI a continuous integration (CI) server that is easy to integrate with GitLab.
Requirements
Please see the requirements documentation for system requirements and more information about the supported operating systems.
Installation
The recommended way to install GitLab is with the Omnibus packages on our package server. Compared to an installation from source, this is faster and less error prone. Just select your operating system, download the respective package (Debian or RPM) and install it using the system's package manager.
There are various other options to install GitLab, please refer to the installation page on the GitLab website for more information.
You can access a new installation with the login root and password 5iveL!fe, after login you are required to set a unique password.
Install a development environment
To work on GitLab itself, we recommend setting up your development environment with the GitLab Development Kit. If you do not use the GitLab Development Kit you need to install and setup all the dependencies yourself, this is a lot of work and error prone. One small thing you also have to do when installing it yourself is to copy the example development unicorn configuration file:
cp config/unicorn.rb.example.development config/unicorn.rb
Instructions on how to start GitLab and how to run the tests can be found in the development section of the GitLab Development Kit.
Software stack
GitLab is a Ruby on Rails application that runs on the following software:
- Ubuntu/Debian/CentOS/RHEL
- Ruby (MRI) 2.1
- Git 1.7.10+
- Redis 2.4+
- MySQL or PostgreSQL
For more information please see the architecture documentation.
Third-party applications
There are a lot of third-party applications integrating with GitLab. These include GUI Git clients, mobile applications and API wrappers for various languages.
GitLab release cycle
Since 2011 a minor or major version of GitLab is released on the 22nd of every month. Patch and security releases are published when needed. New features are detailed on the blog and in the changelog. For more information about the release process see the release documentation. Features that will likely be in the next releases can be found on the feature request forum with the status started and completed.
Upgrading
For upgrading information please see our update page.
Documentation
All documentation can be found on doc.gitlab.com/ce/.
Getting help
Please see Getting help for GitLab on our website for the many options to get help.
Is it any good?
Is it awesome?
Thanks for asking this question Joshua. These people seem to like it.