Merge branch '216174-track-mr-usage' into 'master'

Track merge_requests_users usage data

See merge request gitlab-org/gitlab!32562

changelogs/unreleased/216174-track-mr-usage.yml

+---
+title: Track merge_requests_users usage data
+merge_request: 32562
+author:
+type: changed

db/migrate/20200306160521_add_index_on_author_id_and_created_at_to_events.rb

@@ -4,14 +4,15 @@ class AddIndexOnAuthorIdAndCreatedAtToEvents < ActiveRecord::Migration[6.0]
   include Gitlab::Database::MigrationHelpers
 
   DOWNTIME = false
+  INDEX_NAME = 'index_events_on_author_id_and_created_at'
 
   disable_ddl_transaction!
 
   def up
-    add_concurrent_index :events, [:author_id, :created_at]
+    add_concurrent_index :events, [:author_id, :created_at], name: INDEX_NAME
   end
 
   def down
-    remove_concurrent_index :events, [:author_id, :created_at]
+    remove_concurrent_index :events, INDEX_NAME
   end
 end

db/post_migrate/20200528123703_add_merge_request_partial_index_to_events.rb

+# frozen_string_literal: true
+
+class AddMergeRequestPartialIndexToEvents < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  INDEX_NAME = 'index_events_on_author_id_and_created_at_merge_requests'
+
+  def up
+    add_concurrent_index(
+      :events,
+      [:author_id, :created_at],
+      name: INDEX_NAME,
+      where: "(target_type = 'MergeRequest')"
+    )
+  end
+
+  def down
+    remove_concurrent_index :events, INDEX_NAME
+  end
+end

db/structure.sql

@@ -9708,6 +9708,8 @@ CREATE INDEX index_events_on_action ON public.events USING btree (action);
 
 CREATE INDEX index_events_on_author_id_and_created_at ON public.events USING btree (author_id, created_at);
 
+CREATE INDEX index_events_on_author_id_and_created_at_merge_requests ON public.events USING btree (author_id, created_at) WHERE ((target_type)::text = 'MergeRequest'::text);
+
 CREATE INDEX index_events_on_author_id_and_project_id ON public.events USING btree (author_id, project_id);
 
 CREATE INDEX index_events_on_group_id_partial ON public.events USING btree (group_id) WHERE (group_id IS NOT NULL);
@@ -14048,5 +14050,6 @@ COPY "schema_migrations" (version) FROM STDIN;
 20200527151413
 20200527152116
 20200527152657
+20200528123703
 \.
 

ee/lib/ee/gitlab/usage_data.rb

@@ -39,8 +39,8 @@ module EE
 
         override :uncached_data
         def uncached_data
-          time_period = { created_at: 28.days.ago..Time.current }
-          usage_activity_by_stage_monthly = usage_activity_by_stage(:usage_activity_by_stage_monthly, time_period)
+          usage_activity_by_stage_monthly = usage_activity_by_stage(:usage_activity_by_stage_monthly, default_time_period)
+
           super
             .merge(usage_activity_by_stage)
             .merge(usage_activity_by_stage_monthly)

lib/gitlab/usage_data.rb

@@ -32,6 +32,7 @@ module Gitlab
           .merge(cycle_analytics_usage_data)
           .merge(object_store_usage_data)
           .merge(recording_ce_finish_data)
+          .merge(merge_requests_usage_data(default_time_period))
       end
 
       def to_json(force_refresh: false)
@@ -385,6 +386,27 @@ module Gitlab
         {} # augmented in EE
       end
 
+      # rubocop: disable CodeReuse/ActiveRecord
+      def merge_requests_usage_data(time_period)
+        query =
+          Event
+            .where(target_type: Event::TARGET_TYPES[:merge_request].to_s)
+            .where(time_period)
+
+        merge_request_users = distinct_count(
+          query,
+          :author_id,
+          batch_size: 5_000, # Based on query performance, this is the optimal batch size.
+          start: User.minimum(:id),
+          finish: User.maximum(:id)
+        )
+
+        {
+          merge_requests_users: merge_request_users
+        }
+      end
+      # rubocop: enable CodeReuse/ActiveRecord
+
       def installation_type
         if Rails.env.production?
           Gitlab::INSTALLATION_TYPE
@@ -392,6 +414,10 @@ module Gitlab
           "gitlab-development-kit"
         end
       end
+
+      def default_time_period
+        { created_at: 28.days.ago..Time.current }
+      end
     end
   end
 end

lib/gitlab/utils/usage_data.rb

@@ -49,9 +49,9 @@ module Gitlab
         FALLBACK
       end
 
-      def distinct_count(relation, column = nil, batch: true, start: nil, finish: nil)
+      def distinct_count(relation, column = nil, batch: true, batch_size: nil, start: nil, finish: nil)
         if batch && Feature.enabled?(:usage_ping_batch_counter, default_enabled: true)
-          Gitlab::Database::BatchCount.batch_distinct_count(relation, column, start: start, finish: finish)
+          Gitlab::Database::BatchCount.batch_distinct_count(relation, column, batch_size: batch_size, start: start, finish: finish)
         else
           relation.distinct_count_by(column)
         end

spec/lib/gitlab/usage_data_spec.rb

@@ -575,4 +575,27 @@ describe Gitlab::UsageData, :aggregate_failures do
 
     it_behaves_like 'usage data execution'
   end
+
+  describe '#merge_requests_usage_data' do
+    let(:time_period) { { created_at: 2.days.ago..Time.current } }
+    let(:merge_request) { create(:merge_request) }
+    let(:other_user) { create(:user) }
+    let(:another_user) { create(:user) }
+
+    before do
+      create(:event, target: merge_request, author: merge_request.author, created_at: 1.day.ago)
+      create(:event, target: merge_request, author: merge_request.author, created_at: 1.hour.ago)
+      create(:event, target: merge_request, author: merge_request.author, created_at: 3.days.ago)
+      create(:event, target: merge_request, author: other_user, created_at: 1.day.ago)
+      create(:event, target: merge_request, author: other_user, created_at: 1.hour.ago)
+      create(:event, target: merge_request, author: other_user, created_at: 3.days.ago)
+      create(:event, target: merge_request, author: another_user, created_at: 4.days.ago)
+    end
+
+    it 'returns the distinct count of users using merge requests (via events table) within the specified time period' do
+      expect(described_class.merge_requests_usage_data(time_period)).to eq(
+        merge_requests_users: 2
+      )
+    end
+  end
 end