Fix security scan query timeout

Changelog: other

db/migrate/20210708124229_add_security_scans_created_at_index.rb

+# frozen_string_literal: true
+
+class AddSecurityScansCreatedAtIndex < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  INDEX_NAME = 'index_security_scans_on_created_at'
+
+  def up
+    add_concurrent_index(:security_scans, :created_at, name: INDEX_NAME)
+  end
+
+  def down
+    remove_concurrent_index_by_name(:security_scans, INDEX_NAME)
+  end
+end

db/schema_migrations/20210708124229

+18f7a9a0e9f0b331028951adf2bf6ca9a9fc4a62872f5307ee9d74761ae06deb
\ No newline at end of file

db/structure.sql

@@ -24798,6 +24798,8 @@ CREATE INDEX index_security_findings_on_severity ON security_findings USING btre
 
 CREATE UNIQUE INDEX index_security_findings_on_uuid_and_scan_id ON security_findings USING btree (uuid, scan_id);
 
+CREATE INDEX index_security_scans_on_created_at ON security_scans USING btree (created_at);
+
 CREATE INDEX index_security_scans_on_date_created_at_and_id ON security_scans USING btree (date(timezone('UTC'::text, created_at)), id);
 
 CREATE INDEX index_self_managed_prometheus_alert_events_on_environment_id ON self_managed_prometheus_alert_events USING btree (environment_id);