Add index to ci_builds table for usage_data

To make usage data queries that run on ci_builds
table more performant we need to add new dedicated
index

changelogs/unreleased/230438-usage-data-optimize-usage_activity_by_stage-counters.yml

+---
+title: Add index on ci_builds relation to improve Usage Ping metrics collection performance.
+merge_request: 37581
+author:
+type: added

db/post_migrate/20200908064229_add_partial_index_to_ci_builds_table_on_user_id_name.rb

+# frozen_string_literal: true
+
+class AddPartialIndexToCiBuildsTableOnUserIdName < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  disable_ddl_transaction!
+
+  INDEX_NAME = 'index_partial_ci_builds_on_user_id_name_parser_features'
+  FILTER_CONDITION = <<~SQL
+    (((type)::text = 'Ci::Build'::text) AND
+      ((name)::text = ANY (
+        ARRAY[
+          ('container_scanning'::character varying)::text,
+          ('dast'::character varying)::text,
+          ('dependency_scanning'::character varying)::text,
+          ('license_management'::character varying)::text,
+          ('license_scanning'::character varying)::text,
+          ('sast'::character varying)::text,
+          ('coverage_fuzzing'::character varying)::text,
+          ('secret_detection'::character varying)::text
+        ]
+      ))
+    )
+  SQL
+
+  def up
+    add_concurrent_index(:ci_builds,
+                         [:user_id, :name],
+                         where: FILTER_CONDITION,
+                         name: INDEX_NAME)
+  end
+
+  def down
+    remove_concurrent_index_by_name :ci_builds, INDEX_NAME
+  end
+end

db/schema_migrations/20200908064229

+e73076f6d7540372ee16fe26dcb44e8b84dde69e27c46483ee26883e81059501
\ No newline at end of file

db/structure.sql

@@ -20758,6 +20758,8 @@ CREATE INDEX index_pages_domains_on_wildcard ON pages_domains USING btree (wildc
 
 CREATE UNIQUE INDEX index_partial_am_alerts_on_project_id_and_fingerprint ON alert_management_alerts USING btree (project_id, fingerprint) WHERE (status <> 2);
 
+CREATE INDEX index_partial_ci_builds_on_user_id_name_parser_features ON ci_builds USING btree (user_id, name) WHERE (((type)::text = 'Ci::Build'::text) AND ((name)::text = ANY (ARRAY[('container_scanning'::character varying)::text, ('dast'::character varying)::text, ('dependency_scanning'::character varying)::text, ('license_management'::character varying)::text, ('license_scanning'::character varying)::text, ('sast'::character varying)::text, ('coverage_fuzzing'::character varying)::text, ('secret_detection'::character varying)::text])));
+
 CREATE UNIQUE INDEX index_partitioned_foreign_keys_unique_index ON partitioned_foreign_keys USING btree (to_table, from_table, from_column);
 
 CREATE INDEX index_pat_on_user_id_and_expires_at ON personal_access_tokens USING btree (user_id, expires_at);

spec/migrations/add_partial_index_to_ci_builds_table_on_user_id_name_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20200908064229_add_partial_index_to_ci_builds_table_on_user_id_name.rb')
+
+RSpec.describe AddPartialIndexToCiBuildsTableOnUserIdName do
+  let(:migration) { described_class.new }
+
+  describe '#up' do
+    it 'creates temporary partial index on type' do
+      expect { migration.up }.to change { migration.index_exists?(:ci_builds, [:user_id, :name], name: described_class::INDEX_NAME) }.from(false).to(true)
+    end
+  end
+
+  describe '#down' do
+    it 'removes temporary partial index on type' do
+      migration.up
+
+      expect { migration.down }.to change { migration.index_exists?(:ci_builds, [:user_id, :name], name: described_class::INDEX_NAME) }.from(true).to(false)
+    end
+  end
+end