tdfs4ds.utils.td_context¶
teradataml's current context: is one open, close it with a time limit, forget it.
teradataml changed where it keeps the connection. Up to 20.0.0.10 it is a module
global, teradataml.context.context.td_connection. From 20.0.0.12 the context is
an object, _global_context_instance (top of _context_stack), and the module
global stays None. Code that only read the global saw no connection at all on
20.0.0.12 (0.3.6.2's keep-alive never pinged, and its bounded close returned at
once) while tdml.remove_context() still ran its garbage collector over the
dead connection and blocked forever. Both layouts are read here, once.
tdml.remove_context() sends statements (query band reset, DROP VIEW of its
temporary objects) before closing. Over a connection the network dropped while
idle, the driver waits for an answer that never comes, so a close must be bounded.
Run fn in a daemon thread. Returns (finished, result_or_exception).
Forget the current teradataml connection without sending anything over it.
Close the teradataml context, giving up after timeout seconds.
Returns 'none' (nothing open), 'closed', 'failed' (the close raised;
the context is cleared anyway) or 'abandoned' (it did not return in time:
the context is cleared and the stuck call is left in its daemon thread).