The `Rails` object was not always available in all tasks that require
Redis access, such as `mail_room`, so the constant pointing to the
configuration path was never defined, but we still attempted to access
it in `config_file_name`, resulting in a `NameError` exception.
Further, there was no benefit to defining these paths in a constant to
begin with -- they're only accessed in one place, and it was within the
class where they were being defined. We can just provide them at
run-time instead.
Further _still_, we were calling `File.expand_path` on the absolute path
returned by `Rails.root.join`, which was rather pointless.
Related to !13108. Mostly this is just running the rake task and
changing the task a bit to catch cases like the project already existing
or so. The rake task moves archives to the vendor/project_template
directory, which are checked in too.
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).
setting of the gpg home directory is not thread safe, as the directoy
gets stored on the class.
if multiple threads change the directory at the same time, one of the
threads will be working in the wrong directory.
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.
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.
Rémy Coutable
Douwe Maan
Robert Speicher
Nick Thomas
Jacob Vosmaer
Felipe Artur
Z.J. van de Weg
vanadium23
Yorick Peterse
Dmitriy Zaporozhets
Alexis Reigel
Robert Speicher
Ahmad Sherif
Robin Bobbitt
Bob Van Landuyt
Sean McGivern
Lin Jen-Shin
Sean McGivern
Stan Hu
James Edwards-Jones
Kim "BKC" Carlbäcker