Re: Re: Better backtrace (wasRe: pqReadData() -- backend closed the ch

Well, the bottom line seems to be that there's something broken about
the floating-point support on that box. Look in
/usr/local/pgsql/data/tmp --- I made a trivial test program that just
tries to convert a short integer to a double. I get:

> cat tryit.c
#include <stdio.h>
#include <stdlib.h>

int main()
{
short i = 22;
double d;

d = i;

printf("i = %d, d = %g\n", i, d);
return 0;
}

> gcc tryit.c
> ./a.out
Illegal instruction (core dumped)
> gcc -msoft-float tryit.c
> ./a.out
i = 22, d = 22
> uname -a
FreeBSD jc12.easthighschool.net 4.3-RELEASE FreeBSD 4.3-RELEASE #0: Sat Apr 21 10:54:49 GMT 2001 jkh(at)narf(dot)osd(dot)bsdi(dot)com:/usr/src/sys/compile/GENERIC i386
> gcc -v
Using builtin specs.
gcc version 2.95.3 [FreeBSD] 20010315 (release)
>

I speculate that your box is so old that it has no hardware floating
point at all, and that what we are seeing here is a fault in FreeBSD's
software emulation of the 'fild' (short-to-double) instruction. Or
maybe it's an assembly-time problem. A google search turned up

http://gatekeeper.dec.com/pub/BSD/FreeBSD/FreeBSD-current/src/contrib/binutils/include/opcode/ChangeLog

with the following interesting entry:

2000-05-17 Maciej W. Rozycki <macro(at)ds2(dot)pg(dot)gda(dot)pl>

* i386.h: Use sl_FP, not sl_Suf for fild.

which suggests that older versions of the GNU toolchain may mis-assemble
'fild' instructions.

It'd be worth asking around in BSD-specific mailing lists to see if this
is a known problem; I didn't find anything else in my web search, but I
wasn't trying very hard. I think Postgres is off the hook, in any case.

regards, tom lane