BigW Consortium Gitlab

  1. 28 Nov, 2017 1 commit
    • Reuse authors when rendering event Atom feeds · 63180167
      Yorick Peterse authored
      Previously we'd use "event.author_email" which translates to
      "event.author.email". This would result in an extra query being executed
      _for every event_ just to get the same author's Email address.
      
      Instead of doing all this useless work we can just pass the User object
      returned by "event.author" since:
      
      1. This allows us to re-use the user object's Email address.
      2. Authors are eager-loaded, so this doesn't cause any N+1 queries.
  2. 06 Nov, 2017 1 commit
  3. 06 Oct, 2017 1 commit
  4. 22 Aug, 2017 1 commit
  5. 10 Aug, 2017 1 commit
    • Migrate events into a new format · 0395c471
      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.
  6. 05 Jul, 2017 1 commit
  7. 25 May, 2017 1 commit
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  10. 11 Apr, 2017 3 commits
  11. 10 Apr, 2017 1 commit
  12. 07 Apr, 2017 1 commit
  13. 06 Apr, 2017 3 commits
  14. 03 Apr, 2017 4 commits
  15. 21 Mar, 2017 2 commits
  16. 11 Mar, 2017 1 commit
  17. 15 Feb, 2017 1 commit
  18. 31 Dec, 2016 1 commit
  19. 25 Nov, 2016 1 commit
  20. 23 Nov, 2016 1 commit
    • Remove event caching code · 5371da34
      Yorick Peterse authored
      Flushing the events cache worked by updating a recent number of rows in
      the "events" table. This has the result that on PostgreSQL a lot of dead
      tuples are produced on a regular basis. This in turn means that
      PostgreSQL will spend considerable amounts of time vacuuming this table.
      This in turn can lead to an increase of database load.
      
      For GitLab.com we measured the impact of not using events caching and
      found no measurable increase in response timings. Meanwhile not flushing
      the events cache lead to the "events" table having no more dead tuples
      as now rows are only inserted into this table.
      
      As a result of this we are hereby removing events caching as it does not
      appear to help and only increases database load.
      
      For more information see the following comment:
      https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6578#note_18864037
  21. 07 Nov, 2016 1 commit
  22. 31 Aug, 2016 1 commit
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  25. 28 Jun, 2016 1 commit
  26. 03 Jun, 2016 2 commits
  27. 02 Jun, 2016 1 commit
  28. 31 May, 2016 1 commit
  29. 26 May, 2016 1 commit
  30. 23 May, 2016 1 commit
  31. 16 May, 2016 1 commit