On Thu, Jun 12, 2014 at 12:45 PM, Andres Freund <and...@2ndquadrant.com> wrote: > On 2014-06-12 08:55:59 +0530, Amit Kapila wrote: > > Function pg_create_logical_replication_slot() is trying to > > save slot twice once during CreateInitDecodingContext() and > > then in ReplicationSlotPersist(), isn't it better if we can make > > it do it just once? > > Doesn't work here. In the first save it's not yet marked as persistent - > but we still need to safely reserve the xmin.
Okay, but if it crashes before saving the persistency to permanent file and there remains a .tmp for this replication slot which it created during save of this persistency information, then also xmin will get lost, because during startup it will not consider such a slot. > It's also not something > that should happen very frequently, so I'm not worried about the > overhead. Right, just looking from the purpose of need for same. > > 8. Is there a chance of inconsistency, if pg_restxlog resets the > > xlog and after restart, one of the slots contains xlog position > > older than what is resetted by pg_resetxlog? > > Yes. There's lots of ways to screw over your database by using > pg_resetxlog. Thats right, trying to think if there could be any thing which won't even allow the server to get started due to replication slots after pg_resetxlog. As per my current understanding, I don't think there is any such problem. With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
