On 2014-03-17 14:01:03 -0400, Tom Lane wrote: > Andres Freund <and...@2ndquadrant.com> writes: > > * I wonder if we should make the possible origins a bit more > > general as it's perfectly possible to trigger the problem without > > foreign keys. Maybe: "can arise when a table row that has been updated > > is row locked; that can e.g. happen when foreign keys are used." > > IIUC, this case only occurs when using the new-in-9.3 types of > nonexclusive row locks. I'm willing to bet that the number of > applications using those is negligible; so I think it's all right to not > mention that case explicitly, as long as the wording doesn't say that > foreign keys are the *only* cause (which I didn't).
I actually think the issue could also occur with row locks of other severities (is that the correct term?). Alvaro probably knows better, but if I see correctly it's also triggerable if a backend waits for an updating transaction to finish and follow_updates = true is passed to heap_lock_tuple(). Which e.g. nodeLockRows.c does... Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
