Re: nodeWindowAgg.c IGNORE NULLS abs overflow

Hi Jian,

>> SELECT v,
>> lead(v, -2147483648) OVER w AS respect_nulls,
>> lead(v, -2147483648) IGNORE NULLS OVER w AS ignore_nulls
>> FROM (VALUES (1), (2)) AS t(v)
>> WINDOW w AS (ORDER BY v);
>>
>> should return all NULL values for column ignore_nulls.
>>
>> The fix is to replace the abs function in nodeWindowAgg.c with pg_abs_s32.

I confirmed the problem. It seems it's a corner case bug: only happens
when offset = -2147483648. Anyway, bug is a bug.

Attached is a patch which should be ready for commit IMO. I haven't
changed the C code part from yours. I have changed the regression test
part to use low case SQL statements which fits in better with
surroundings.

Regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp