Re: pika failing since the per-column collation patch

Le 18 févr. 2011 à 08:26, Tom Lane a écrit :

> =?iso-8859-1?Q?R=E9mi_Zara?= <remi_zara(at)mac(dot)com> writes:
>> Le 12 févr. 2011 à 18:51, Peter Eisentraut a écrit :
>>> It's only failing on this one machine, but there isn't anything
>>> platform-specific in this code, so I'd look for memory management faults
>>> on the code or a compiler problem. Try with lower optimization for a
>>> start.
>
>> Same failure with -O0 (and more shared memory).
>
> Note that the query that is failing is an intentional probe of
> robustness:
>
> -- check that we can apply functions taking ANYARRAY to pg_stats ...
> -- such functions must protect themselves if varying element type isn't OK
> select max(histogram_bounds) from pg_stats;
> ERROR: cannot compare arrays of different element types
>
> pika is instead showing
>
> ERROR: locale operation to be invoked, but no collation was derived
>
> which some trawling through the code says is coming from varstr_cmp
> when fn_collation didn't get set on the call.
>
> Hypothesis: the platform-dependency here is just one of row ordering,
> to wit, on most platforms the scan of pg_statistic fails before it gets
> to the case where the collation issue is triggered. I'm suspicious that
> if two text arrays get compared via this code path, fn_collation fails
> to get set, and it's not a platform-specific omission.
>
> It'd be helpful if you could identify the specific values that are
> getting compared at the moment of the failure.
>

Hi,

Here is what I get after adding an elog in varstr_cmp:

WARNING: Comparing "B011 " and "<fetch first clause> in subqueries^?^?\xa0"
ERROR: locale operation to be invoked, but no collation was derived
STATEMENT: select max(histogram_bounds) from pg_stats;

Regards,

Rémi Zara