Optimize counts.terraform_reports usage ping counter

(cherry picked from commit c32430c6)

changelogs/unreleased/230437-usage-data-optimize-counts-terraform_reports.yml

+---
+title: Optimize counts.terraform_reports usage ping counter
+merge_request: 39499
+author:
+type: performance

db/post_migrate/20200811211536_add_index_to_ci_job_artifacts_for_terraform_reports_id.rb

+# frozen_string_literal: true
+
+class AddIndexToCiJobArtifactsForTerraformReportsId < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  INDEX_NAME = 'index_ci_job_artifacts_id_for_terraform_reports'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :ci_job_artifacts, :id, where: 'file_type = 18', name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name :ci_job_artifacts, INDEX_NAME
+  end
+end

db/schema_migrations/20200811211536

+d4ea24092289f6dba294c502b8ce89748165973fb2d7989fa7615433599a0c0c
\ No newline at end of file

db/structure.sql

@@ -19203,6 +19203,8 @@ CREATE UNIQUE INDEX index_ci_instance_variables_on_key ON public.ci_instance_var
 
 CREATE INDEX index_ci_job_artifacts_for_terraform_reports ON public.ci_job_artifacts USING btree (project_id, id) WHERE (file_type = 18);
 
+CREATE INDEX index_ci_job_artifacts_id_for_terraform_reports ON public.ci_job_artifacts USING btree (id) WHERE (file_type = 18);
+
 CREATE INDEX index_ci_job_artifacts_on_expire_at_and_job_id ON public.ci_job_artifacts USING btree (expire_at, job_id);
 
 CREATE INDEX index_ci_job_artifacts_on_file_store ON public.ci_job_artifacts USING btree (file_store);