When you perform a long running select statement on 2 hawq tables (join) from JDBC and illegally kill the JDBC client (CTRL ALT DEL) before completion of the query the 2 tables remained locked even when the query completes on the server.
The lock is visible via PG_locks. One cannot kill the query via SELECT pg_terminate_backend(393937). The only way to get rid of it is to kill -9 from linux or restart hawq but this can kill other things as well.
The JDBC client I am using is Aqua Data Studio.
I can provide exact steps to reproduce if required