Re: [HACKERS] server crash on recursive function invocation

[Tom Lane]

Ali Baba <[EMAIL PROTECTED]> writes:
> i was just trying recursive function invocation and got a server crash when i 
> changed a GUC variable max_stack_depth,  to a high number. 

There's a reason why that variable is a superuser-only setting: you're
supposed to have some clue what you're doing when you change it ;-)

If you need more stack space, what you generally have to do is adjust
the ulimit setting that the postmaster is started under.  You can set
max_stack_depth up to a few hundred K less than the postmaster's
ulimit -s setting, but not more.

(We wouldn't even have the variable if there were a sufficiently
portable way to find out the ulimit stack depth automatically, but
there's not one that I know of.)

regards, tom lane

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Re: [HACKERS] server crash on recursive function invocation

[Andrew Dunstan]

Ali Baba said:
>
> hi,
> i was just trying recursive function invocation and got a server crash
> when i changed a GUC variable max_stack_depth,  to a high number.
> fallowing is what i have tried.
>
> select max_val from pg_settings where name='max_stack_depth'; --
> returns 2097151 set max_stack_depth=2097151;
> CREATE OR REPLACE FUNCTION func() RETURNS INT AS $$
> DECLARE
> x int;
> BEGIN
>  null;
>  x := func();
>  return 0;
> END;
> $$ LANGUAGE PLPGSQL;
> select func();
> and the server get crashed.
>
>
> Any ideas?
>


what the heck did you expect with an infinitely recursive function?

cheers

andrew



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[HACKERS] server crash on recursive function invocation

[Ali Baba]

hi,i was just trying recursive function invocation and got a server crash when i changed a GUC variable max_stack_depth,  to a high number. fallowing is what i have tried.select max_val from pg_settings where name='max_stack_depth'; -- returns 2097151set max_stack_depth=2097151;CREATE OR REPLACE FUNCTION func() RETURNS INT AS $$DECLAREx int;BEGIN  null;  x := func();  return 0;END;$$ LANGUAGE PLPGSQL;select func(); and the server get crashed.Any ideas?Thanks,--Usman
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