In 1.0, we added new APIs to GTM so that vacuum can run with global XID and snapshot. We may need more improvement to use this. It is wonderful if Mason provides a patch to fix this. Regards; --- Koichi Suzuki 2013/12/11 Michael Paquier <michael.paquier@xxxxxxxxx>: > On Tue, Dec 10, 2013 at 11:00 PM, Mason Sharp <msharp@xxxxxxxxxxxxxxxx> wrote: >> In our StormDB fork (now TransLattice Storm) I made some changes to address >> some issues that were uncovered with XC. I am not sure if it will address >> this specific issue above, but in most cases we make it an error instead of >> falling back to a local XID like XC does (imagine if a node cannot reach GTM >> and autovacuum starts cleaning up data with local XIDs and snapshots) . > Yep, falling back to a local xid when GTM is not reachable has been > done since the beginning of the project. Considering that as a bug > using the argument that it endangers data visibility, such a patch > should be back-patched as well. Some insight on those remarks from the > core team would be welcome though. > >> Also, we use GTM for getting XIDs for authentication and for autovacuum >> launcher because in concurrency testing not doing so results in the same XID >> being consumed by other sessions and causing hanging and other transaction >> problems. The bottom line is falling back to local XIDs and snapshots should >> almost always be avoided (initdb is ok). > Check. > >> Our code is a bit different from vanilla XC, but I can try to put together a >> similar patch soon. > This would be welcome. > >> As a community I feel we should prioritize more on testing and bug fixing >> like the reported issue and replicated table handling than on new features >> like the merged coordinator and datanode project. > Definitely, *normal* developers cannot afford spending so much time on > projects as big as that. One of the big things that I see missing is a > public instance of an XC buildfarm, by using for example the buildfarm > code of Postgres that simply fetches the code from git, and kicks > in-core tests. For XC this should be restricted though to regressions, > and compilation. pg_upgrade or isolation tests are not really > working... > > Regards, > -- > Michael > > ------------------------------------------------------------------------------ > Rapidly troubleshoot problems before they affect your business. Most IT > organizations don't have a clear picture of how application performance > affects their revenue. With AppDynamics, you get 100% visibility into your > Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! > http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk > _______________________________________________ > Postgres-xc-general mailing list > Postgres-xc-general@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/postgres-xc-general -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
