Re: stack depth limit exceeded problem.

[Thomas Hallgren <thhal(at)mailblocks(dot)com>]

Martijn van Oosterhout wrote:
> Linux has sigaltstack so you can catch the stack overflow signal (and
> other signals obviously, but that's its main use), but it's not terribly
> portable.
>
I rely on the signal handler that the JVM uses for page-faults (which a 
stack overflow generally amounts to) and fpe exeptions so I know that 
they will generate java exceptions in a controlled way (which I in turn 
translate to elog(ERROR) on the main thread).

> What you really need to do is set the stack_base_ptr every
> time you execute postgres with a new stack; that preserves existing
> semantics.
>
Exactly!. What I'd really like to do in threads other than main is:

void* currentBase = switchStackBase(stackBaseOfMyThread);
PG_TRY
{
  /* service the call here */
  switchStackBase(currentBase);
}
PG_CATCH
{
  switchStackBase(currentBase);
  /* generate Java exception as usual */
}

> Signals are the only way the kernel can pass control unexpectedly so if
> you handle those, postgres would never know it's threaded. I do wonder
> if there are any other assumptions made...
>
> Have a nice day,

You too. And thanks for all your input.

Regards,
Thomas Hallgren