Fujii Masao wrote: > On Thu, Jun 10, 2010 at 5:06 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > Josh Berkus <j...@agliodbs.com> writes: > >> The fact that failover current does *not* terminate existing queries and > >> transactions was regarded as a feature by the audience, rather than a > >> bug, when I did demos of HS/SR. ?Of course, they might not have been > >> thinking of the delay for writes. > > > >> If there were an easy way to make the trigger file cancel all running > >> queries, apply remaining logs and come up, then I'd vote for that for > >> 9.0. ?I think it's the more desired behavior by most users. ?However, > >> I'm opposed to any complex solutions which might delay 9.0 release. > > > > My feeling about it is that if you want fast failover you should not > > have your failover target server configured as hot standby at all, let > > alone hot standby with a long max_standby_delay. ?Such a slave could be > > very far behind on applying WAL when the crunch comes, and no amount of > > query killing will save you from that. ?Put your long-running standby > > queries on a different slave instead. > > > > We should consider whether we can improve the situation in 9.1, but it > > is not a must-fix for 9.0; especially when the correct behavior isn't > > immediately obvious. > > OK. Let's revisit in 9.1. > > I attached the proposal patch for 9.1. The patch treats max_standby_delay > as zero (i.e., cancels all the conflicting queries immediately), ever since > the trigger file is created. So we can cause a recovery to end without > waiting for any lock held by queries, and minimize the failover time. > OTOH, queries which don't conflict with a recovery survive the failover.
Should this be added to the first 9.1 commitfest? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + None of us is going to be here forever. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
