This works by searching the raw source code for any references to
commonly used ActiveRecord methods. While not bulletproof it saves us
from having to list hundreds of methods by hand. It also ensures that
(most) newly added methods are instrumented automatically.
This _only_ instruments models defined in app/models, should a model
reside somewhere else (e.g. somewhere in lib/) it _won't_ be
instrumented.
This ensures we don't end up wasting resources by tracking method calls
that only take a few microseconds. By default the threshold is 10
milliseconds but this can be changed using the gitlab.yml configuration
file.
InfluxDB escapes double quotes upon output which makes it a pain to deal
with. This ensures that if we're using PostgreSQL we don't store any
queries containing double quotes in InfluxDB, solving the escaping
problem.
When using instrument_methods/instrument_instance_methods we only want
to instrument methods defined directly in a class, not those included
via mixins (e.g. whatever RSpec throws in during development).
In case an externally included method _has_ to be instrumented we can
still use the regular instrument_method/instrument_instance_method
methods.
The methods Instrumentation.instrument_methods and
Instrumentation.instrument_instance_methods can be used to instrument
all methods of a module at once.
The use of ActiveSupport would slow down instrumented method calls by
about 180x due to:
1. ActiveSupport itself not being the fastest thing on the planet
2. caller_locations() having quite some overhead
The use of caller_locations() has been removed because it's not _that_
useful since we already know the full namespace of receivers and the
names of the called methods.
The use of ActiveSupport has been replaced with some custom code that's
generated using eval() (which can be quite a bit faster than using
define_method).
This new setup results in instrumented methods only being about 35-40x
slower (compared to non instrumented methods).
The previous setup wasn't exactly fast, resulting in instrumented method
calls taking about 600 times longer than non instrumented calls
(including any ActiveSupport code involved). With this commit this
slowdown has been reduced to around 185 times.
This adds the ability to write application metrics (e.g. SQL timings) to
InfluxDB. These metrics can in turn be visualized using Grafana, or
really anything else that can read from InfluxDB. These metrics can be
used to track application performance over time, between different Ruby
versions, different GitLab versions, etc.
== Transaction Metrics
Currently the following is tracked on a per transaction basis (a
transaction is a Rails request or a single Sidekiq job):
* Timings per query along with the raw (obfuscated) SQL and information
about what file the query originated from.
* Timings per view along with the path of the view and information about
what file triggered the rendering process.
* The duration of a request itself along with the controller/worker
class and method name.
* The duration of any instrumented method calls (more below).
== Sampled Metrics
Certain metrics can't be directly associated with a transaction. For
example, a process' total memory usage is unrelated to any running
transactions. While a transaction can result in the memory usage going
up there's no accurate way to determine what transaction is to blame,
this becomes especially problematic in multi-threaded environments.
To solve this problem there's a separate thread that takes samples at a
fixed interval. This thread (using the class Gitlab::Metrics::Sampler)
currently tracks the following:
* The process' total memory usage.
* The number of file descriptors opened by the process.
* The amount of Ruby objects (using ObjectSpace.count_objects).
* GC statistics such as timings, heap slots, etc.
The default/current interval is 15 seconds, any smaller interval might
put too much pressure on InfluxDB (especially when running dozens of
processes).
== Method Instrumentation
While currently not yet used methods can be instrumented to track how
long they take to run. Unlike the likes of New Relic this doesn't
require modifying the source code (e.g. including modules), it all
happens from the outside. For example, to track `User.by_login` we'd add
the following code somewhere in an initializer:
Gitlab::Metrics::Instrumentation.
instrument_method(User, :by_login)
to instead instrument an instance method:
Gitlab::Metrics::Instrumentation.
instrument_instance_method(User, :save)
Instrumentation for either all public model methods or a few crucial
ones will be added in the near future, I simply haven't gotten to doing
so just yet.
== Configuration
By default metrics are disabled. This means users don't have to bother
setting anything up if they don't want to. Metrics can be enabled by
editing one's gitlab.yml configuration file (see
config/gitlab.yml.example for example settings).
== Writing Data To InfluxDB
Because InfluxDB is still a fairly young product I expect the worse.
Data loss, unexpected reboots, the database not responding, you name it.
Because of this data is _not_ written to InfluxDB directly, instead it's
queued and processed by Sidekiq. This ensures that users won't notice
anything when InfluxDB is giving trouble.
The metrics worker can be started in a standalone manner as following:
bundle exec sidekiq -q metrics
The corresponding class is called MetricsWorker.
Fix ci_projects migration by using the value only from latest row [ci skip]
This is needed, because for some projects we have duplicate ci_projects.
This was introduced by lack of DB uniqueness on ci_projects.gitlab_id.
The MR fixes edge case by selecting value from latest.
/cc @yorickpeterse
Fixes: gitlab-org/gitlab-ce#4123
See merge request !2133
Revert sidebar position for issue and merge request
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
cc @creamzy @skyruler
See merge request !2132
Fix ux issue with "This issue will be closed automatically" message
1. Make a nice box for "issue will be closed automatically" message
2. move it below emoji navbar. Otherwise looks wierd.
Fixes#4134
# Before
# After
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
See merge request !2129
Api support for requesting starred projects for user
Closes#4112
Note: probably targets the wrong release in the `CHANGELOG`, though 8.4 was not there yet
See merge request !2127
Move MR Builds tab next to Commits
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/4132
@dzaporozhets We've got two people who feel strongly about this now, @sytses filed an issue for it :)
See merge request !2128
Clean up ci yaml doc
* Fix headings so that they are picked up by doc.gitlab.com
* Stick to 80 characters
* Clean up some examples
See merge request !2052
Update rerun to remove celluloid as dependency
After sidekiq 4 migration, we no longer need celluloid. `rerun` recent version also removed it from its dependency, so by getting this MR merged, we can solve #3797
See merge request !2088
Link to correct (source) project on MR builds tab
Used to link to `gitlab-org/gitlab-ce/commits/<branch-name>`, now links to correct project.
See merge request !2115
Yorick Peterse
Robert Speicher
Jacob Vosmaer
Kamil Trzciński
Dmitriy Zaporozhets
Achilleas Pipinellis
Rubén Dávila
Douwe Maan
Zeger-Jan van de Weg