Dne 5.11.2015 19:02 napsal uživatel "Merlin Moncure" <mmonc...@gmail.com>: > > 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. >
I am sorry, I see a consensus between you and Stephen only. Regards Pavel > merlin
