Any alter table statement that doesn't explicitly set the default time to live will reset it to 0. That can be very dangerous for time series use cases, which rely on all data being eventually expired, and a default TTL of 0 means data never being expired. Fixes #5048. Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com> Message-Id: <20200402211653.25603-1-raphaelsc@scylladb.com>