1. 24 Jan, 2019 1 commit
  2. 18 Jul, 2018 1 commit
  3. 08 Sep, 2017 1 commit
    • Yorick Peterse's avatar
      Rework how recent push events are retrieved · 83355336
      Yorick Peterse authored
      Whenever you push to a branch GitLab will show a button to create a
      merge request (should one not exist already). The underlying code to
      display this data was quite inefficient. For example, it involved
      multiple slow queries just to figure out what the most recent push event
      was.
      
      This commit changes the way this data is retrieved so it's much faster.
      This is achieved by caching the ID of the last push event on every push,
      which is then retrieved when loading certain pages. Database queries are
      only executed if necessary and the cached data is removed automatically
      once a merge request has been created, or 2 hours after being stored.
      
      A trade-off of this approach is that we _only_ track the last event.
      Previously if you were to push to branch A and B then create a merge
      request for branch B we'd still show the widget for branch A. As of this
      commit this is no longer the case, instead we will only show the widget
      for the branch you pushed to most recently. Once a merge request exists
      the widget is no longer displayed. Alternative solutions are either too
      complex and/or too slow, hence the decision was made to settle for this
      trade-off.
      
      Performance Impact
      ------------------
      
      In the best case scenario (= a user didn't push anything for more than 2
      hours) we perform a single Redis GET per page. Should there be cached
      data we will run a single (and lightweight) SQL query to get the
      event data from the database. If a merge request already exists we will
      run an additional DEL to remove the cache key.
      
      The difference in response timings can vary a bit per project. On
      GitLab.com the 99th percentile of time spent in User#recent_push hovers
      between 100 milliseconds and 1 second, while the mean hovers around 50
      milliseconds. With the changes in this MR the expected time spent in
      User#recent_push is expected to be reduced down to just a few
      milliseconds.
      
      Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/35990
      83355336
  4. 10 Aug, 2017 1 commit
    • Yorick Peterse's avatar
      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.
      0395c471
  5. 02 Aug, 2017 1 commit
  6. 27 Jul, 2017 2 commits
  7. 11 Jul, 2017 1 commit
  8. 14 Apr, 2017 3 commits
  9. 01 Feb, 2017 1 commit
  10. 20 Oct, 2016 2 commits
    • Callum Dryden's avatar
      Differentiate the expire from leave event · f488b9f7
      Callum Dryden authored
      At the moment we cannot see weather a user left a project due to their
      membership expiring of if they themselves opted to leave the project.
      This adds a new event type that allows us to make this differentiation.
      Note that is not really feasable to go back and reliably fix up the
      previous events. As a result the events for previous expire removals
      will remain the same however events of this nature going forward will be
      correctly represented.
      f488b9f7
    • Callum Dryden's avatar
      Differentiate the expire from leave event · 9124310f
      Callum Dryden authored
      At the moment we cannot see weather a user left a project due to their
      membership expiring of if they themselves opted to leave the project.
      This adds a new event type that allows us to make this differentiation.
      Note that is not really feasable to go back and reliably fix up the
      previous events. As a result the events for previous expire removals
      will remain the same however events of this nature going forward will be
      correctly represented.
      9124310f
  11. 09 Aug, 2016 1 commit
  12. 12 Jul, 2016 1 commit
  13. 09 Dec, 2015 1 commit
  14. 15 Sep, 2015 1 commit
  15. 12 Feb, 2015 1 commit
  16. 25 Mar, 2014 1 commit