Why do metrics indexes with Hour and Day precisions stop updating after upgrade to 7.x?

This issue is to be expected with an upgrade from 6.x to 7.x. See the Downsampling Data Packing feature of the ElasticSearch storage.

You may simply delete all expired *-day_xxxxx and *-hour_xxxxx(xxxxx is a timestamp) indexes. Currently, SkyWalking uses the metrics name-xxxxx and metrics name-month_xxxxx indexes only.