BigW Consortium Gitlab

  1. 20 Sep, 2017 1 commit
    • Remove redundant WHERE from event queries · 9a3e4b8d
      Yorick Peterse authored
      The default scope in Event would add a "WHERE author_id IS NOT NULL"
      clause to every query. Now that "events.author_id" has a NOT NULL clause
      set this filter is redundant and we can safely remove it.
      
      In this commit we also add a validation on events.author_id (previously
      only defined in PushEvent) just in case something tries to create data
      without an author ID. This way we can present a nicer error message
      compared to PostgreSQL's foreign key error messages.
      
      Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/38129
  2. 12 Sep, 2017 1 commit
  3. 07 Sep, 2017 1 commit
    • 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
  4. 06 Sep, 2017 1 commit
    • Finish migration to the new events setup · 235b105c
      Yorick Peterse authored
      This finishes the procedure for migrating events from the old format
      into the new format. Code no longer uses the old setup and the database
      tables used during the migration process are swapped, with the old table
      being dropped.
      
      While the database migration can be reversed this will 1) take a lot of
      time as data has to be coped around 2) won't restore data in the
      "events.data" column as we have no way of restoring this.
      
      Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/37241
  5. 22 Aug, 2017 1 commit
  6. 21 Aug, 2017 1 commit
  7. 10 Aug, 2017 2 commits
    • Use a specialized class for querying events · aac1de46
      Yorick Peterse authored
      This changes various controllers to use the new EventCollection class
      for retrieving events. This class uses a JOIN LATERAL query on
      PostgreSQL to retrieve queries in a more efficient way, while falling
      back to a simpler / less efficient query for MySQL.
      
      The EventCollection class also includes a limit on the number of events
      to display to prevent malicious users from cycling through all events,
      as doing so could put a lot of pressure on the database.
      
      JOIN LATERAL is only supported on PostgreSQL starting with version 9.3.0
      and as such this optimisation is only used when using PostgreSQL 9.3 or
      newer.
    • 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.
  8. 06 Jul, 2017 1 commit
  9. 21 Jun, 2017 1 commit
  10. 07 Jun, 2017 1 commit
  11. 06 Jun, 2017 1 commit
    • Introduce an Events API · ad3e180e
      Mark Fletcher authored
      * Meld the following disparate endpoints:
       * `/projects/:id/events`
       * `/events`
       * `/users/:id/events`
      + Add result filtering to the above endpoints:
       * action
       * target_type
       * before and after dates
  12. 31 May, 2017 1 commit
  13. 04 May, 2017 1 commit
  14. 26 Apr, 2017 1 commit
  15. 21 Mar, 2017 1 commit
  16. 24 Feb, 2017 1 commit
  17. 23 Feb, 2017 3 commits
  18. 13 Feb, 2017 4 commits
  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. 16 Nov, 2016 1 commit
  22. 09 Nov, 2016 1 commit
  23. 27 Oct, 2016 1 commit
  24. 20 Oct, 2016 2 commits
    • 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.
    • 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.
  25. 11 Oct, 2016 1 commit
  26. 07 Oct, 2016 1 commit
    • Fix Event#reset_project_activity updates · 16626409
      Stan Hu authored
      !6678 removed the lease from Event#reset_project_activity, but it wasn't
      actually updating the project's last_activity_at timestamp properly.
      The WHERE clause would always return no matching projects. The spec
      passed occasionally because the created_at timestamp was automatically
      set to last_activity_at.
  27. 04 Oct, 2016 1 commit
    • Remove lease from Event#reset_project_activity · c9bcfc63
      Yorick Peterse authored
      Per GitLab.com's performance metrics this method could take up to 5
      seconds of wall time to complete, while only taking 1-2 milliseconds of
      CPU time. Removing the Redis lease in favour of conditional updates
      allows us to work around this.
      
      A slight drawback is that this allows for multiple threads/processes to
      try and update the same row. However, only a single thread/process will
      ever win since the UPDATE query uses a WHERE condition to only update
      rows that were not updated in the last hour.
      
      Fixes gitlab-org/gitlab-ce#22473
  28. 20 Sep, 2016 1 commit
  29. 19 Sep, 2016 1 commit
  30. 30 Aug, 2016 1 commit
  31. 06 Jul, 2016 1 commit
  32. 04 Jul, 2016 1 commit
  33. 28 Jun, 2016 1 commit