Add index on historical_data (recorded_at) to improve queries (!68435) · Merge requests · GitLab.org / GitLab

Krasimir Angelov requested to merge 334761-index-historical-data-on-recorded-at into master Aug 18, 2021

What does this MR do?

This MR adds an index on historical_data (recorded_at) to improve some queries.

We have the following places where we query on historical_data.recorded_at:

These all benefit from having an index on historical_data(recorded_at).

Execution plans before:

Execution plans after:

We can see Seq Scan is changed to Index Scan after adding the index.

While working on this I've noticed we have HistoricalData.up_until scope (using this column) that is not used, so removed it as part of this MR.

Related to #334761 (closed).

Database migrations

$ bundle exec rails db:migrate:up VERSION=20210818034001
== 20210818034001 IndexHistoricalDataOnRecordedAt: migrating ==================
-- transaction_open?()
   -> 0.0000s
-- index_exists?(:historical_data, :recorded_at, {:name=>"index_historical_data_on_recorded_at", :algorithm=>:concurrently})
   -> 0.0017s
-- execute("SET statement_timeout TO 0")
   -> 0.0005s
-- add_index(:historical_data, :recorded_at, {:name=>"index_historical_data_on_recorded_at", :algorithm=>:concurrently})
   -> 0.0051s
-- execute("RESET statement_timeout")
   -> 0.0005s
== 20210818034001 IndexHistoricalDataOnRecordedAt: migrated (0.0257s) =========

Down

$ bundle exec rails db:migrate:down VERSION=20210818034001
== 20210818034001 IndexHistoricalDataOnRecordedAt: reverting ==================
-- transaction_open?()
   -> 0.0000s
-- indexes(:historical_data)
   -> 0.0025s
-- execute("SET statement_timeout TO 0")
   -> 0.0005s
-- remove_index(:historical_data, {:algorithm=>:concurrently, :name=>"index_historical_data_on_recorded_at"})
   -> 0.0035s
-- execute("RESET statement_timeout")
   -> 0.0006s
== 20210818034001 IndexHistoricalDataOnRecordedAt: reverted (0.0140s) =========

Does this MR meet the acceptance criteria?

Conformity

I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
I have added/updated documentation, or it's not needed. (Is documentation required?)
I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
I have self-reviewed this MR per code review guidelines.
This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
I have followed the style guides.
This change is backwards compatible across updates, or this does not apply.

Availability and Testing

I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
I have tested this MR in all supported browsers, or it's not needed.
I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

Label as security and @ mention @gitlab-com/gl-security/appsec
The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
Security reports checked/validated by a reviewer from the AppSec team

Related to #334761 (closed)

Edited Aug 18, 2021 by Andreas Brandl

Add index on historical_data (recorded_at) to improve queries