Data in the pageview_hourly table is sanitized from the deploy day of the sanitization process.
We need to update the table with sanitized data, based on the data already in the table.
Process:
Create a new temporary pageview external table.
Fill the new table with sanitized pageview using existing pageview_hourly table for the given month.
Move exisitng pageview_hourly into a safe place, in order not to loose that data if anything go wrong. - DON'T DELETE THAT DATA YET :)
Move the newly computed data in the empty pageview_hourly folders.