1. 22 Aug, 2017 5 commits
  2. 17 Aug, 2017 3 commits
  3. 14 Aug, 2017 1 commit
    • Yorick Peterse's avatar
      Cache the number of forks of a project · 970143440d40
      Yorick Peterse authored
      The number of forks of a project doesn't change very frequently and
      running a COUNT(*) every time this information is requested can be quite
      expensive. We also end up running such a COUNT(*) query at least twice
      on the homepage of a project.
      
      By caching this data and refreshing it when necessary we can reduce
      project homepage loading times by around 60 milliseconds (based on the
      timings of https://gitlab.com/gitlab-org/gitlab-ce).
      970143440d40
  4. 10 Aug, 2017 2 commits
    • Robert Speicher's avatar
      24244dd4cac7
    • Yorick Peterse's avatar
      Migrate events into a new format · 20d17d1129f6
      Yorick Peterse authored
      This commit migrates events data in such a way that push events are
      stored much more efficiently. This is done by creating a shadow table
      called "events_for_migration", and a table called "push_event_payloads"
      which is used for storing push data of push events. The background
      migration in this commit will copy events from the "events" table into
      the "events_for_migration" table, push events in will also have a row
      created in "push_event_payloads".
      
      This approach allows us to reclaim space in the next release by simply
      swapping the "events" and "events_for_migration" tables, then dropping
      the old events (now "events_for_migration") table.
      
      The new table structure is also optimised for storage space, and does
      not include the unused "title" column nor the "data" column (since this
      data is moved to "push_event_payloads").
      
      == Newly Created Events
      
      Newly created events are inserted into both "events" and
      "events_for_migration", both using the exact same primary key value. The
      table "push_event_payloads" in turn has a foreign key to the _shadow_
      table. This removes the need for recreating and validating the foreign
      key after swapping the tables. Since the shadow table also has a foreign
      key to "projects.id" we also don't have to worry about orphaned rows.
      
      This approach however does require some additional storage as we're
      duplicating a portion of the events data for at least 1 release. The
      exact amount is hard to estimate, but for GitLab.com this is expected to
      be between 10 and 20 GB at most. The background migration in this commit
      deliberately does _not_ update the "events" table as doing so would put
      a lot of pressure on PostgreSQL's auto vacuuming system.
      
      == Supporting Both Old And New Events
      
      Application code has also been adjusted to support push events using
      both the old and new data formats. This is done by creating a PushEvent
      class which extends the regular Event class. Using Rails' Single Table
      Inheritance system we can ensure the right class is used for the right
      data, which in this case is based on the value of `events.action`. To
      support displaying old and new data at the same time the PushEvent class
      re-defines a few methods of the Event class, falling back to their
      original implementations for push events in the old format.
      
      Once all existing events have been migrated the various push event
      related methods can be removed from the Event model, and the calls to
      `super` can be removed from the methods in the PushEvent model.
      
      The UI and event atom feed have also been slightly changed to better
      handle this new setup, fortunately only a few changes were necessary to
      make this work.
      
      == API Changes
      
      The API only displays push data of events in the new format. Supporting
      both formats in the API is a bit more difficult compared to the UI.
      Since the old push data was not really well documented (apart from one
      example that used an incorrect "action" nmae) I decided that supporting
      both was not worth the effort, especially since events will be migrated
      in a few days _and_ new events are created in the correct format.
      20d17d1129f6
  5. 09 Aug, 2017 1 commit
  6. 08 Aug, 2017 1 commit
  7. 02 Aug, 2017 1 commit
  8. 01 Aug, 2017 3 commits
  9. 28 Jul, 2017 1 commit
  10. 27 Jul, 2017 2 commits
  11. 24 Jul, 2017 1 commit
  12. 20 Jul, 2017 1 commit
  13. 18 Jul, 2017 1 commit
  14. 13 Jul, 2017 1 commit
  15. 11 Jul, 2017 1 commit
  16. 06 Jul, 2017 2 commits
  17. 05 Jul, 2017 3 commits
  18. 04 Jul, 2017 1 commit
  19. 03 Jul, 2017 2 commits
  20. 30 Jun, 2017 3 commits
  21. 29 Jun, 2017 2 commits
  22. 28 Jun, 2017 2 commits