Harden deployment counters

Use a more specialized index and use start and finish parameters

changelogs/unreleased/221184-optimize-rolling-28-counters-for-.yml

+---
+title: Optimize deployment counters for last 28 days
+merge_request: 35892
+author:
+type: performance

db/post_migrate/20200704161600_add_index_on_id_and_status_and_created_at_to_deployments.rb

+# frozen_string_literal: true
+
+class AddIndexOnIdAndStatusAndCreatedAtToDeployments < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :deployments, [:id, :status, :created_at]
+    remove_concurrent_index :deployments, [:id, :status]
+  end
+
+  def down
+    add_concurrent_index :deployments, [:id, :status]
+    remove_concurrent_index :deployments, [:id, :status, :created_at]
+  end
+end

db/structure.sql

@@ -18986,7 +18986,7 @@ CREATE INDEX index_deployments_on_environment_id_and_iid_and_project_id ON publi
 
 CREATE INDEX index_deployments_on_environment_id_and_status ON public.deployments USING btree (environment_id, status);
 
-CREATE INDEX index_deployments_on_id_and_status ON public.deployments USING btree (id, status);
+CREATE INDEX index_deployments_on_id_and_status_and_created_at ON public.deployments USING btree (id, status, created_at);
 
 CREATE INDEX index_deployments_on_id_where_cluster_id_present ON public.deployments USING btree (id) WHERE (cluster_id IS NOT NULL);
 
@@ -23639,6 +23639,7 @@ COPY "schema_migrations" (version) FROM STDIN;
 20200702123805
 20200703154822
 20200704143633
+20200704161600
 20200706005325
 20200706170536
 20200707071941

lib/gitlab/usage_data.rb

@@ -84,9 +84,9 @@ module Gitlab
             auto_devops_enabled: count(::ProjectAutoDevops.enabled),
             auto_devops_disabled: count(::ProjectAutoDevops.disabled),
             deploy_keys: count(DeployKey),
-            deployments: count(Deployment),
-            successful_deployments: count(Deployment.success),
-            failed_deployments: count(Deployment.failed),
+            deployments: deployment_count(Deployment),
+            successful_deployments: deployment_count(Deployment.success),
+            failed_deployments: deployment_count(Deployment.failed),
             environments: count(::Environment),
             clusters: count(::Clusters::Cluster),
             clusters_enabled: count(::Clusters::Cluster.enabled),
@@ -169,9 +169,9 @@ module Gitlab
       def system_usage_data_monthly
         {
           counts_monthly: {
-            deployments: count(Deployment.where(last_28_days_time_period)),
-            successful_deployments: count(Deployment.success.where(last_28_days_time_period)),
-            failed_deployments: count(Deployment.failed.where(last_28_days_time_period)),
+            deployments: deployment_count(Deployment.where(last_28_days_time_period)),
+            successful_deployments: deployment_count(Deployment.success.where(last_28_days_time_period)),
+            failed_deployments: deployment_count(Deployment.failed.where(last_28_days_time_period)),
             personal_snippets: count(PersonalSnippet.where(last_28_days_time_period)),
             project_snippets: count(ProjectSnippet.where(last_28_days_time_period))
           }.tap do |data|
@@ -616,12 +616,26 @@ module Gitlab
         end
       end
 
+      def deployment_minimum_id
+        strong_memoize(:deployment_minimum_id) do
+          ::Deployment.minimum(:id)
+        end
+      end
+
+      def deployment_maximum_id
+        strong_memoize(:deployment_maximum_id) do
+          ::Deployment.maximum(:id)
+        end
+      end
+
       def clear_memoized
         clear_memoization(:issue_minimum_id)
         clear_memoization(:issue_maximum_id)
         clear_memoization(:user_minimum_id)
         clear_memoization(:user_maximum_id)
         clear_memoization(:unique_visit_service)
+        clear_memoization(:deployment_minimum_id)
+        clear_memoization(:deployment_maximum_id)
       end
 
       # rubocop: disable CodeReuse/ActiveRecord
@@ -645,6 +659,10 @@ module Gitlab
       def filtered_omniauth_provider_names
         omniauth_provider_names.reject { |name| name.starts_with?('ldap') }
       end
+
+      def deployment_count(relation)
+        count relation, start: deployment_minimum_id, finish: deployment_maximum_id
+      end
     end
   end
 end

spec/lib/gitlab/usage_data_spec.rb

@@ -18,7 +18,10 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
       end
 
       it 'clears memoized values' do
-        %i(issue_minimum_id issue_maximum_id user_minimum_id user_maximum_id unique_visit_service).each do |key|
+        values = %i(issue_minimum_id issue_maximum_id
+                    user_minimum_id user_maximum_id unique_visit_service
+                    deployment_minimum_id deployment_maximum_id)
+        values.each do |key|
           expect(described_class).to receive(:clear_memoization).with(key)
         end