When client connections use threadpool, i.e. configuration has:
thread_handling = pool-of-threads it turned out that during wsrep
replication shutdown, not all client connections could be closed.
Reason was that some client threads has stmt_da in state DA_EOF,
and this state was earlier used to detect if client connection
was issuing SHUTDOWN command.
To fix this, the connection executing SHUTDOWN is now detected by
looking at the actual command being executed:
thd->get_command() == COM_SHUTDOWN
During replication shutdown, all other connections but the
SHUTDOWN executor, are terminated.
This commit has new mtr test galera.galera_threadpool, which
opens a number of threadpool client connections, and then
restarts the node to verify that connections in threadpool are
terminated during shutdown.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>
