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.
The method User#projects_limit_left would run "personal_projects.count"
but such a query is not memoized. As a result multiple calls to
User#projects_limit_left would result in multiple COUNT(*) queries being
executed.
To work around this this commit adds User#personal_projects_count which
simply memoizes the result of the COUNT(*) in an instance variable.
When sign-in is disabled:
- skip password expiration checks
- prevent password reset requests
- don’t show Password tab in User Settings
- don’t allow login with username/password for Git over HTTP requests
- render 404 on requests to Profiles::PasswordsController
In CE only the admin has access to all private groups & projects. In EE also an
auditor can have full private access.
To overcome merge conflicts, or accidental incorrect access rights, abstract
this out in `User#full_private_access?`.
`User#admin?` now only should be used for admin-only features. For private
access-related features `User#full_private_access?` should be used.
Backported from gitlab-org/gitlab-ee!2199
This commit introduces the usage of Common Table Expressions (CTEs) to
efficiently retrieve nested group hierarchies, without having to rely on
the "routes" table (which is an _incredibly_ inefficient way of getting
the data). This requires a patch to ActiveRecord (found in the added
initializer) to work properly as ActiveRecord doesn't support WITH
statements properly out of the box.
Unfortunately MySQL provides no efficient way of getting nested groups.
For example, the old routes setup could easily take 5-10 seconds
depending on the amount of "routes" in a database. Providing vastly
different logic for both MySQL and PostgreSQL will negatively impact the
development process. Because of this the various nested groups related
methods return empty relations when used in combination with MySQL.
For project authorizations the logic is split up into two classes:
* Gitlab::ProjectAuthorizations::WithNestedGroups
* Gitlab::ProjectAuthorizations::WithoutNestedGroups
Both classes get the fresh project authorizations (= as they should be
in the "project_authorizations" table), including nested groups if
PostgreSQL is used. The logic of these two classes is quite different
apart from their public interface. This complicates development a bit,
but unfortunately there is no way around this.
This commit also introduces Gitlab::GroupHierarchy. This class can be
used to get the ancestors and descendants of a base relation, or both by
using a UNION. This in turn is used by methods such as:
* Namespace#ancestors
* Namespace#descendants
* User#all_expanded_groups
Again this class relies on CTEs and thus only works on PostgreSQL. The
Namespace methods will return an empty relation when MySQL is used,
while User#all_expanded_groups will return only the groups a user is a
direct member of.
Performance wise the impact is quite large. For example, on GitLab.com
Namespace#descendants used to take around 580 ms to retrieve data for a
particular user. Using CTEs we are able to reduce this down to roughly 1
millisecond, returning the exact same data.
== On The Fly Refreshing
Refreshing of authorizations on the fly (= when
users.authorized_projects_populated was not set) is removed with this
commit. This simplifies the code, and ensures any queries used for
authorizations are not mutated because they are executed in a Rails
scope (e.g. Project.visible_to_user).
This commit includes a migration to schedule refreshing authorizations
for all users, ensuring all of them have their authorizations in place.
Said migration schedules users in batches of 5000, with 5 minutes
between every batch to smear the load around a bit.
== Spec Changes
This commit also introduces some changes to various specs. For example,
some specs for ProjectTeam assumed that creating a personal project
would _not_ lead to the owner having access, which is incorrect. Because
we also no longer refresh authorizations on the fly for new users some
code had to be added to the "empty_project" factory. This chunk of code
ensures that the owner's permissions are refreshed after creating the
project, something that is normally done in Projects::CreateService.
Every time a user logs in or out, the Trackable attributes are written to the
database. This is causing a lot of load on the database, for data that isn't
really critical.
So to avoid the database being hammered, add a Gitlab::ExclusiveLease before
writing trackable attributes to the database. This lease expires after an hour,
so only when the attributes were written more than an hour ago, they can be
written again. Otherwise they are ignored.
Michael Kozono
Yorick Peterse
Robert Speicher
Dmitriy Zaporozhets
Alexis Reigel
Rémy Coutable
Bob Van Landuyt
Tiago Botelho
Sean McGivern
Robin Bobbitt
Nathan Neulinger
Paul Charlton
Toon Claes
Grzegorz Bizon
Douwe Maan
DJ Mountney
Lin Jen-Shin
Nick Thomas
Valery Sizov
blackst0ne
Robert Speicher
Ruben Davila
Bob Van Landuyt
Douwe Maan
James Lopez