Re: V3: Idle in transaction cancellation

On Thursday 02 December 2010 00:48:53 Kevin Grittner wrote:
> Andres Freund <andres@anarazel.de> wrote:
> > On Tuesday 19 October 2010 16:18:29 Kevin Grittner wrote:
> >> For SSI purposes, it would be highly desirable to be able to set
> >> the SQLSTATE and message generated when the canceled transaction
> >> terminates.
> > 
> > Ok, I implemented that capability, but the patch feels somewhat
> > wrong to me,
> 
> > so its a separate patch on top the others:
> The patch is in context diff format, applies with minor offsets,
> compiles and passes regression tests.
> 
> I have to admit that after reading the patch, I think I previously
> misunderstood the scope of it.  Am I correct in reading that the
> main thrust of this is to improve error handling on standbys?  Is
> there any provision for one backend to cause a *different* backend
> which is idle in a transaction to terminate cleanly when it attempts
> to process its next statement?  (That is what I was hoping to find,
> for use in the SSI patch.)
Do you wan't to terminate it immediately or on next statement?

You might want to check out SendProcSignal() et al.

> Anyway, if the third patch file is only there because of my request,
> I think it might be best to focus on the first two as a solution for
> the standby issues this was originally meant to address, and then to
> look at an API for the usage I have in mind after that is settled.
Besides that I dont like the implementation very much, I think its generally a 
good idea...