nodetool refreshsizeestimates 

Refresh system.size_estimates table.

Refreshes system.size_estimates table. Use when huge amounts of data are inserted or truncated which can result in size estimates becoming incorrect.

Synopsis 

$ nodetool <options> refreshsizeestimates
DataStax Enterprise 5.0 Installer No-Services and tarball installations:
installation_location/resources/cassandra/bin
Options
Short Long Description
-h --host Hostname or IP address.
-p --port Port number.
-pwf --password-file Password file path.
-pw --password Password.
-u --username Remote JMX agent username.
-- Separates an option from an argument that could be mistaken for a option.