Re: Hot Standby, max_connections and max_prepared_transactions

On Thu, 2009-09-03 at 22:22 +0300, Heikki Linnakangas wrote:
> Simon Riggs wrote:
> > I propose we just accept that both max_connections and
> > max_prepared_transactions need to be set correctly for recovery to work.
> > This will make the state transitions more robust and it will avoid
> > spurious and hard to test error messages.
> > 
> > Any objections to me removing this slice of code from the patch? 
> 
> Umm, what slice of code? I don't recall any code trying to make it work.

Well, its there. Perhaps the full functionality has been clipped in
recent changes, but there are still unwanted ramifications in the design
that I think would be best to remove. No loss of functionality, just HS
won't activate unless max_connections is set >= value on primary.

Since max_prepared_transactions already has this same problem in the
current code I see no reason to fuss. We can always put in more flexible
code later.

State change code in StartupXLog(), Snapshots disabled code in
GetSnapshotData(), ProcArray->allowStandbySnapshots etc..

-- Simon Riggs           www.2ndQuadrant.com