Hi
dblink in 8.3 blocks without any possibility of interrupting it while
waiting for an answer from the remote server. Here is a strace
[pid 27607] rt_sigaction(SIGPIPE, {SIG_IGN}, {SIG_IGN}, 8) = 0
[pid 27607] sendto(56, "Q\0\0\0008lock table travelhit.booking_code in
exclusive mode\0", 57, 0, NULL, 0) = 57
[pid 27607] rt_sigaction(SIGPIPE, {SIG_IGN}, {SIG_IGN}, 8) = 0
[pid 27607] poll([{fd=56, events=POLLIN|POLLERR}], 1, -1) = ?
ERESTART_RESTARTBLOCK (To be restarted)
[pid 27607] --- SIGTERM (Terminated) @ 0 (0) ---
[pid 27607] rt_sigreturn(0xf) = -1 EINTR (Interrupted system call)
[pid 27607] poll(
As you can see I'm trying to lock the table travelhit.booking_code,
which blocks because someone else is already holding that lock. When
I send a SIGTERM to the backend, the poll() syscalll is interruped -
but immediatly restarted.
I'm not sure how a proper fix for this could look like, since the
blocking actually happens inside libpq - but this certainly makes
working with dblink painfull...
regards, Florian Pflug
