One case is conflicting transactions T1 and T2 with different domain id, in
optimistic parallel replication in non-GTID mode. Then T2 will
wait_for_prior_commit on T1; and if T1 got a row lock wait on T2 it would
hang, as different domains caused the deadlock kill to be skipped in
thd_rpl_deadlock_check().
More generally, if we have transactions T1 and T2 in one domain/master
connection, and independent transactions U in another, then we can
still deadlock like this:
T1 row low wait on U
U row lock wait on T2
T2 wait_for_prior_commit on T1
This commit enforces the deadlock kill in these cases. If the waited-for
transaction is speculatively applied, then it will be deadlock killed in
case of a conflict, even if the two transactions are in different domains
or master connections.
Reviewed-by: Andrei Elkin <andrei.elkin@mariadb.com>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
