The issue seems similar to
HIVE-9720, but only happens with partitioned tables. I only tested with Hive 3.1 in Impala dev environment.
The issue can be reproduced by the following statements (it doesn't matter whether Hive or Impala runs them with the exception of compute/show stats).
create database db1;
create database db2;
create table db1.t(i int) partitioned by (p int);
insert into db1.t partition (p=1) values (2);
compute stats db1.t; -- needs Impala
alter table db1.t rename to db2.t;
show column stats db2.t; -- needs Impala, null count and ndv will be incorrectly -1
drop table db2.t; -- this will hang