Re: [HACKERS] Some thoughts about multi-server sync rep configurations

2016-12-27 Thread Thomas Munro
On Wed, Dec 28, 2016 at 4:21 PM, Craig Ringer wrote: > On 28 December 2016 at 08:14, Thomas Munro > wrote: > >> 3. No server must allow a transaction to be visible that hasn't been >> flushed on N standby servers. We already prevent that on the primary > > Only if the primary doesn't restart. W

Re: [HACKERS] Some thoughts about multi-server sync rep configurations

2016-12-27 Thread Craig Ringer
On 28 December 2016 at 08:14, Thomas Munro wrote: > 3. No server must allow a transaction to be visible that hasn't been > flushed on N standby servers. We already prevent that on the primary Only if the primary doesn't restart. We don't persist the xact masking used by sync rep at the moment.

[HACKERS] Some thoughts about multi-server sync rep configurations

2016-12-27 Thread Thomas Munro
Hi, Sync rep with multiple standbys allows queries run on standbys to see transactions that haven't been flushed on the configured number of standbys. That means that it's susceptible to lost updates or a kind of "dirty read" in certain cluster reconfiguration scenarios. To close that gap, we wo