From: Kyotaro Horiguchi <horikyota....@gmail.com>
> It seems to respond to a statement-cancel signal immediately while
> waiting for a coming byte. However, seems to wait forever while
> waiting a space in send-buffer. (Is that mean the session will be
> stuck if it sends a large chunk of bytes while the network is down?)
What part makes you worried about that? libpq's send processing?
I've just examined pgfdw_cancel_query(), too. As below, it uses a hidden 30
second timeout. After all, postgres_fdw also relies on timeout already.
/*
* If it takes too long to cancel the query and discard the result, assume
* the connection is dead.
*/
endtime = TimestampTzPlusMilliseconds(GetCurrentTimestamp(), 30000);
> After receiving a signal, it closes the problem connection. So the
> local session is usable after that but the fiailed remote sessions are
> closed and created another one at the next use.
I couldn't see that the problematic connection is closed when the cancellation
fails... Am I looking at a wrong place?
/*
* If connection is already unsalvageable, don't touch it
* further.
*/
if (entry->changing_xact_state)
break;
Regards
Takayuki Tsunakawa
