On Wed, Apr 16, 2014 at 6:56 PM, Andres Freund <and...@2ndquadrant.com>wrote:
> Hi, > > On 2014-04-16 18:51:41 +0200, Magnus Hagander wrote: > > I'm thinking it could be interesting to know how many times (or in some > > other useful unit than "times" - how often) a specific replication slot > has > > "blocked" xlog rotation. Since this AFAIK only happens during > checkpoints, > > it seems it should be "reasonably cheap" to track? It would serve as an > > indicator of which slave(s) are having enough trouble keeping up to > > potentially cause issues. > > The xlog removal code just check the "global minimum" required LSN - it > doesn't check the individual slots. So you'd need to add a bit more code > to that location. But it'd be easy. > Do we have statistics there somewhere - how often that global minimum blocks something? That on it's own might be a start :) But I think I'd just monitor/graph the byte difference for all slots > using pg_replication_slots... > Yeah, that would work when monitored continously. I was more looking for the view of "hey, could this be what happened" into a system that did not previously have any monitoring installed and therefor no such history. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/
