GitLab Next

This updates the index on ci_pipelines (project_id, ref, status) to include the id column. This reduces the time to get the latest pipeline for a ref (e.g. "master") from up to 25-30 ms down to 1 millisecond.

See the commit message for more details.

Migration Output

== 20171121144800 CiPipelinesIndexOnProjectIdRefStatusId: migrating ===========
-- transaction_open?()
   -> 0.0000s
-- execute("SET statement_timeout TO 0")
   -> 0.0004s
-- add_index(:ci_pipelines, [:project_id, :ref, :status, :id], {:algorithm=>:concurrently})
   -> 0.0183s
-- transaction_open?()
   -> 0.0000s
-- select_one("SELECT current_setting('server_version_num') AS v")
   -> 0.0004s
-- execute("SET statement_timeout TO 0")
   -> 0.0002s
-- remove_index(:ci_pipelines, {:algorithm=>:concurrently, :column=>[:project_id, :ref, :status]})
   -> 0.0109s
== 20171121144800 CiPipelinesIndexOnProjectIdRefStatusId: migrated (0.0305s) ==

Database Checklist

When adding migrations:

• Updated db/schema.rb
• Added a down method so the migration can be reverted
• Added the output of the migration(s) to the MR body
• Added the execution time of the migration(s) to the MR body
• Made sure the migration won't interfere with a running GitLab cluster, for example by disabling transactions for long running migrations

When adding indexes:

• Described the need for these indexes in the MR body
• Made sure existing indexes can not be reused instead

General Checklist

• Changelog entry added, if necessary
• Review
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together