Hi, Tom Thank you for comments.
> Tomonari Katsumata <t.katsumata1...@gmail.com> writes: > >> Why is it better to do this with a privilege, rather than just using > >> pg_hba.conf? > > > > You are right. > > Handling with pg_hba.conf is an easy way. > > > But I think many users think about switch over, so > > the pg_hba.conf is same on master and standby. > > it's not convinient that we have to rewrite pg_hba.conf > > whenever switch over occurs. > > > In the other hand, using a privilege, although we have to prepare > > each roles before, we don't need to rewrite pg_hba.conf. > > > That sounds good, but if the behavior is controlled by a privilege > (ie, it's stored in system catalogs) then it's impossible to have > different settings on different slave servers --- or indeed to change > the settings locally on a slave at all. You can only change settings > on the master and let the change replicate to all the slaves. > Yes, I'm thinking changing settings on the master and the settings are propagating to all slaves. > Quite aside from whether you want to manage things like that, what happens if > your master has crashed and you find you need to change the settings on > the way to getting a slave to take over? > > The crash-recovery worry is one of the main reasons that things like > pg_hba.conf aren't stored in system catalogs already. It's not always > convenient to need a running server before you can change the settings. > I understand that the approach in my patch(using pribileges for controlling its behavior) does not match the policy. But I'm still thinking I should put a something to controle the behavior. Then, how about to add a new option "standby_mode" to Database Connection Control Functions like application_name. ex: primary_conninfo = 'port=5432 standby_mode=master-cascade' primary_conninfo = 'port=5432 standby_mode=master-only' primary_conninfo = 'port=5432 standby_mode=cascade-only' I think it will be able to do same control with privilege controlling. And it won't be contrary to the policy(no data is stored in system catalogs). Because it is corner-case, I should not do anything about this? (Am I concerning too much?) regards, -------- NTT Software Corporation Tomonari Katsumata
