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@narf.osd.bsdi.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
with the following interesting entry:
2000-05-17 Maciej W. Rozycki <macro@ds2.pg.gda.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
Import Notes
Reply to msg id not found: F1316XOIRUlRWXopokh0000cc66@hotmail.comReference msg id not found: F1316XOIRUlRWXopokh0000cc66@hotmail.com
On Wed, 1 Aug 2001 16:07:59 +0000 (UTC), Tom Lane <tgl@sss.pgh.pa.us> wrote:
Well, the bottom line seems to be that there's something broken about
the floating-point support on that box. Look in
uname -a
FreeBSD jc12.easthighschool.net 4.3-RELEASE FreeBSD 4.3-RELEASE #0: Sat Apr 21 10:54:49 GMT 2001 jkh@narf.osd.bsdi.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 upwhich 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
I recompiled the kernel replacing
options MATH_EMULATE
with
options GPL_MATH_EMULATE
and I am now able to access the database normally.
As an experiment, I had another 486SX (no hardware fpu) which showed
the exact same problem when I transplanted the hard drive. So it
looks like this may be a problem which will show up on the older
486 machines, but can be worked around by recompiling the kernel
with the alternate math emulation code.
I sent a report of your findings to one of the freebsd mailing lists.
Thanks again, Tom.