Thanks a lot for fixing #38, I really appreciate the active maintenance of this project!

Unfortunately, this change to get_table_names which seems unrelated to fixing #38 degrades the performance a lot since the calls of get_columns cause one additional request per table. It can also trigger a lot of warnings since get_type is called in get_columns.

This also affects has_table which prevents me from upgrading to the newest version of elasticsearch-dbapi.

Maybe this change can be reverted or solved in some other way? Simply adding an lru_cache decorator could also be an option.