Re: On a somewhat disappointing correspondence (was: max_standby_delay considered harmful)

Kevin Grittner wrote:
> Simon Riggs <simon@2ndQuadrant.com> wrote:
>  
> I've refrained from comment on max_standby_delay because I have
> neither read the patch nor am likely to be an early adopter of HS;
> however, as a potential eventual user I have to say that the
> semantics for this GUC proposed by Simon seem sane and useful to me.
> 
> Certainly the documentation would need to be clear on the pitfalls
> of using something other than 0 or -1, and there were technical
> issues raised on the thread outside the scope of the semantics of
> the GUC, but the issues around clock sync and transfer time ring of
> FUD.  We sync our central router to a bank of atomic clocks around
> the world, and sync every server to the router -- if a server drifts
> we would have much bigger problems than this GUC would pose, so we
> monitor that and make loud noises should something drift.
>  
> Are there other controls that would be useful?  Undoubtedly.  Should
> they be added to 9.0?  I'm not in a position to say.  I don't see
> the point of ripping out one potentially useful control, which
> *might* be sufficient for 9.0 because someone might choose to use it
> inappropriately.  Just make sure it's documented well enough.

We are not very good at _removing_ functionality/GUCs, and based on the
discussion so far, I think there is a very slim chance we would get it
right for 9.0, which is why I suggested converting it to a boolean and
revisiting this for 9.1.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com