Re: Unresolved error 0xC0000409 on Windows Server

On Sun, Nov 11, 2012 at 12:22 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Matthew Gerber <gerber(dot)matthew(at)gmail(dot)com> writes:
> > On Sun, Nov 11, 2012 at 11:19 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> How long is "long"?
>
> > I was seeing queries with around 5000-7000 "UNION ALL" statements.
>
> Hm. I experimented with test queries created like so:
>
> perl -e 'print "SELECT 1 a, 2 b, 3 c\n"; print "UNION ALL SELECT 1 a, 2 b,
> 3 c\n" foreach (1..8200);' | psql
>
> On the machine I tried this on, it works up to about 8200 and then fails
> in the way I'd expect:
>
> ERROR: stack depth limit exceeded
> HINT: Increase the configuration parameter "max_stack_depth" (currently
> 2048kB), after ensuring the platform's stack depth limit is adequate.
>
> But then when I cranked it up to 80000, kaboom:
>
> connection to server was lost
>
> Inspection of the core dump shows transformSetOperationTree is the
> problem --- it's recursing but lacks a check_stack_depth test.
> So that's easy to fix, but I wonder why the critical depth limit seems
> to be so much less on your machine. I get the expected error up to
> about 65000 UNION ALLs --- why is yours crashing at a tenth of that?
>

Tom,

Interesting. I really have no idea why mine seemed to fail so much sooner.
I recalled my 5k-7k figure from memory, so I might be off on that, but
probably not by an order of magnitude. In any case, it sounds like you know
how to fix the problem. Should I file this as a bug report or will you take
care of it from here?

Best,
Matt