Mysql server requires to explicitly state the database in the query
It sounds like 5.7.19 jumped the gun.

----- 2016-02-05 5.7.11 General Availability -- Functionality Added or Changed -- -----


  The mysql_kill() ( /doc/refman/5.7/en/mysql-kill.html ), mysql_list_fields() ( /doc/refman/5.7/en/mysql-list-fields.html ), mysql_list_processes() ( /doc/refman/5.7/en/mysql-list-processes.html ), and mysql_refresh() ( /doc/refman/5.7/en/mysql-refresh.html ) C API functions are deprecated and will be removed in a future version of MySQL. The same is true of the corresponding COM_PROCESS_KILL, COM_FIELD_LIST, COM_PROCESS_INFO, and COM_REFRESH client/server protocol commands. Instead, use mysql_query() ( /doc/refman/5.7/en/mysql-query.html ) to execute a KILL ( /doc/refman/5.7/en/kill.html ), SHOW COLUMNS ( /doc/refman/5.7/en/show-columns.html ), SHOW PROCESSLIST ( /doc/refman/5.7/en/show-processlist.html ), or FLUSH ( /doc/refman/5.7/en/flush.html ) statement, respectively. 


Recommend you post a bug with bugs.mysql.com .