magento/magento2#: Add a new index for cron_schedule table

Author: atwixfirster

app/code/Magento/Cron/etc/db_schema.xml

@@ -28,5 +28,9 @@
             <column name="scheduled_at"/>
             <column name="status"/>
         </index>
+        <index referenceId="CRON_SCHEDULE_SCHEDULE_ID_STATUS" indexType="btree">
+            <column name="schedule_id"/>
+            <column name="status"/>
+        </index>
     </table>
 </schema>

app/code/Magento/Cron/etc/db_schema_whitelist.json

@@ -12,10 +12,11 @@
         },
         "index": {
             "CRON_SCHEDULE_JOB_CODE": true,
-            "CRON_SCHEDULE_SCHEDULED_AT_STATUS": true
+            "CRON_SCHEDULE_SCHEDULED_AT_STATUS": true,
+            "CRON_SCHEDULE_SCHEDULE_ID_STATUS": true
         },
         "constraint": {
             "PRIMARY": true
         }
     }
-}
+}