Commit 1618461d authored by Kamil Trzciński's avatar Kamil Trzciński

Merge branch 'tc-db-explain-analyze' into 'master'

Add activerecord-explain-analyze gem

See merge request gitlab-org/gitlab-ce!29051
parents 66cf0c02 be472673
......@@ -403,6 +403,7 @@ gem 'ruby-prof', '~> 0.17.0'
gem 'rbtrace', '~> 0.4', require: false
gem 'memory_profiler', '~> 0.9', require: false
gem 'benchmark-memory', '~> 0.1', require: false
gem 'activerecord-explain-analyze', '~> 0.1', require: false
# OAuth
gem 'oauth2', '~> 1.4'
......
......@@ -38,6 +38,9 @@ GEM
activemodel (= 5.1.7)
activesupport (= 5.1.7)
arel (~> 8.0)
activerecord-explain-analyze (0.1.0)
activerecord (>= 4)
pg
activerecord_sane_schema_dumper (1.0)
rails (>= 5, < 6)
activesupport (5.1.7)
......@@ -1012,6 +1015,7 @@ DEPENDENCIES
RedCloth (~> 4.3.2)
ace-rails-ap (~> 4.1.0)
acme-client (~> 2.0.2)
activerecord-explain-analyze (~> 0.1)
activerecord_sane_schema_dumper (= 1.0)
acts-as-taggable-on (~> 6.0)
addressable (~> 2.5.2)
......
......@@ -654,6 +654,35 @@ and related tools such as:
- <https://explain.depesz.com/>
- <http://tatiyants.com/postgres-query-plan-visualization/>
## Producing query plans
There are a few ways to get the output of a query plan. Of course you
can directly run the `EXPLAIN` query in the `psql` console, or you can
follow one of the other options below.
### Rails console
Using the [`activerecord-explain-analyze`](https://github.com/6/activerecord-explain-analyze)
you can directly generate the query plan from the Rails console:
```ruby
pry(main)> require 'activerecord-explain-analyze'
=> true
pry(main)> Project.where('build_timeout > ?', 3600).explain(analyze: true)
Project Load (1.9ms) SELECT "projects".* FROM "projects" WHERE (build_timeout > 3600)
(pry):12
=> EXPLAIN for: SELECT "projects".* FROM "projects" WHERE (build_timeout > 3600)
Seq Scan on public.projects (cost=0.00..2.17 rows=1 width=742) (actual time=0.040..0.041 rows=0 loops=1)
Output: id, name, path, description, created_at, updated_at, creator_id, namespace_id, ...
Filter: (projects.build_timeout > 3600)
Rows Removed by Filter: 14
Buffers: shared hit=2
Planning time: 0.411 ms
Execution time: 0.113 ms
```
### Chatops
GitLab employees can also use our chatops solution, available in Slack using the
`/chatops` slash command. You can use chatops to get a query plan by running the
following:
......
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