Horton

Re: [Bug Fix]ECPG: cancellation of significant digits on ECPG

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Higuchi, Daisuke" <higuchi.daisuke@jp.fujitsu.com>
Cc: "'Dmitry Dolgov'" <9erthalion6@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-11-14T01:09:37Z
Lists: pgsql-hackers 
"Higuchi, Daisuke" <higuchi.daisuke@jp.fujitsu.com> writes:
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us] 
>> So I think that we ought to unconditionally make the sqlda value's digit 
>> buffer look just like the one we're copying, even when ndigits = 0, 
>> which just requires removing the tests on ndigits.

> I agree with you. Seeing this thread[1], 'if (ndigits = 0)' was introduced only to avoid memcpy() crash. I do not know this solution was best or not, but no crash occurs in the current version. So, I also think 'if (ndigits = 0)' should be removed.

Hmmm ... looking at PGTYPESnumeric_from_asc, it seems like the current
behavior is different from what was described in that old thread; the only
case where a digit buffer wouldn't be created is a NaN.  But maybe a crash
could occur for NaN.  Perhaps we should use "if (num->sign !=
NUMERIC_NAN)" as a guard?

			regards, tom lane

Commits

  1. Second try at fixing numeric data passed through an ECPG SQLDA.

  2. Fix incorrect results for numeric data passed through an ECPG SQLDA.