Re: check for interrupts in set_rtable_names

On Fri, Nov 13, 2015 at 3:13 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:
>> Someone sent my server a deranged query, it tripped my
>> auto_explain.log_min_duration setting, that hit some kind of
>> pathological case while assigning aliases, and now it sits
>> uninterruptibly in set_rtable_names for hours.
>
>> Is there any reason we can't check for interrupts in set_rtable_names,
>> like the attached?
>
> There's probably no reason not to do that, but I'd be much more interested
> in eliminating the slowness to begin with ...

I was thinking about that as well, but I don't think that would be
back-patchable, at least not the way I was envisioning it.

I was thinking of detecting bad cases (had to count to over 10 before
finding a novel name, more than 10 times) and then switching from an
object-local count, to a global count, for the numbers to add to the
name. But that would be a behavior change under some conditions.

I think the code says it clearer than prose, so crude first attempt at
that attached.

Cheers,

Jeff