On Wed, Nov 4, 2015 at 4:15 PM, Stephen Frost <sfr...@snowman.net> wrote: > * Joshua D. Drake (j...@commandprompt.com) wrote: >> On 11/04/2015 01:55 PM, Stephen Frost wrote: >> >* Joe Conway (m...@joeconway.com) wrote: >> >>On 11/04/2015 01:24 PM, Alvaro Herrera wrote: >> >>>I agree with Pavel. Having a transaction timeout just does not make any >> >>>sense. I can see absolutely no use for it. An idle-in-transaction >> >>>timeout, on the other hand, is very useful. >> >> >> >>+1 -- agreed >> > >> >I'm not sure of that. I can certainly see a use for transaction >> >timeouts- after all, they hold locks and can be very disruptive in the >> >long run. Further, there are cases where a transaction is normally very >> >fast and in a corner case it becomes extremely slow and disruptive to >> >the rest of the system. In those cases, having a timeout for it is >> >valuable. >> >> Yeah but anything holding a lock that long can be terminated via >> statement_timeout can it not? > > Well, no? statement_timeout is per-statement, while transaction_timeout > is, well, per transaction. If there's a process which is going and has > an open transaction and it's holding locks, that can be an issue. > > To be frank, my gut feeling is that transaction_timeout is actually more > useful than statement_timeout.
Exactly. statement_timeout is weak because it resets for every statement regardless of transaction. Similarly, pg_cancel_backend is weak because it only works if a backend is actually in statement regardless of transaction state (reading this thread, it's clear that this is not widely known even among -hackers which further reinforces the point). Thus, I think we have consensus that transaction_timeout is good -- it would deprecate statement_timeout essentially. Likewise, pg_cancel_transaction is good and would deprecate pg_cancel_backend; it's hard for me to imagine a scenario where a user would call pg_cancel_backend if pg_cancel_transaction were to be available. merlin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers