Re: jsonpath

On Sun, Apr 07, 2019 at 03:03:58AM +0300, Alexander Korotkov wrote:
>On Sun, Apr 7, 2019 at 2:37 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> writes:
>> > Thus, contents of unused function makes test fail or pass. So far, it
>> > looks like a compiler bug. Any thoughts?
>>
>> Yeah :-(. The fact that we've not seen a similar failure on any other
>> machines points in that direction, too. Maybe it's some other aspect
>> of the machine's toolchain, like flex or bison, but that's not that
>> much different from our standpoint.
>>
>> There's a lot of stuff I don't especially like about jsonpath_scan,
>> for instance I think the "init" arguments to resizeString etc are
>> a pretty error-prone and unmaintainable way to do things. But
>> I don't see anything that looks like it'd be a portability hazard
>> that would explain this.
>>
>> I still have a nagging feeling that there's a wild store somewhere
>> in here, but I don't know how to find it based on the limited
>> evidence we've got.
>
>Yeah, it might be not because compiler error. It might depend on
>memory layout. So existence of extra function changes memory layout
>and, in turn, causes an error. I will try to disassemble
>jsonpath_scan.o and see whether content of yyparse2 influences
>assembly of other functions.
>

Have you tried other compiler version / different optimization level? Or
running it under valgrind. Not sure how difficult that is on Windows.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services