Replicating _all tables

If all sites in your system are in the same application database, the base tables already contain data for each of the sites, so the _all tables are not populated and are simply views to the base tables. In that case, replication of _all table data is not necessary.

For on-premise only: If at least one site is in a separate database, and you are replicating data to/from that site, the _all tables are populated.