On 6/14/16 12:37 PM, Robert Haas wrote:
> ERROR: can't generate random numbers because you haven't specified a seed
>
> ...to which the user will reply, "oh yes I did; in fact I ran SELECT
> magic_setseed(42) just before I ran the offending query!". They'll
> then contact an expert (hopefully) who will very possibly spend a lot
> of time troubleshooting the wrong thing. If the message says:
>
> ERROR: can't generate random numbers because you haven't specified a seed
> CONTEXT: parallel worker, PID 62413
>
> ...then the expert has a very good chance of guessing what has gone
> wrong right away.
My updated opinion is to keep the context but remove the PID. I can see
that as this feature is being introduced, we will want to know that
something is happening inside a parallel worker. Maybe in the future
we'll have it all figured out and won't need the context anymore. But
the PID is not useful by the time you see the message. The server log
should contain a trace of the PIDs if you need to do deep digging.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services