Re: [HACKERS] Bug in to_timestamp().

From: Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>
To: Artur Zakirov <a(dot)zakirov(at)postgrespro(dot)ru>
Cc: "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Dmitry Dolgov <9erthalion6(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, amul sul <sulamul(at)gmail(dot)com>, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, Alex Ignatov <a(dot)ignatov(at)postgrespro(dot)ru>, Bruce Momjian <bruce(at)momjian(dot)us>, amul sul <sul_amul(at)yahoo(dot)co(dot)in>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [HACKERS] Bug in to_timestamp().
Date: 2018-08-14 15:38:56
Message-ID: CAPpHfdtPPYzXVYefKeRrf9nbPspXnq3KCx2HfXwWpw+9yQ_rZQ@mail.gmail.com
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On Thu, Aug 2, 2018 at 9:06 PM Alexander Korotkov
<a(dot)korotkov(at)postgrespro(dot)ru> wrote:
> On Thu, Aug 2, 2018 at 6:17 PM Alexander Korotkov
> <a(dot)korotkov(at)postgrespro(dot)ru> wrote:
> > After some experiments I found that when you mix spaces and separators
> > between two fields, then Oracle takes into account only length of last
> > group of spaces/separators.
> >
> > # SELECT to_timestamp('2018- -01 02', 'YYYY---- --- --MM-DD') FROM
> > dual2018-01-01 00:00:00 -10:00
> > (length of last spaces/separators group is 2)
> >
> > # SELECT to_timestamp('2018- -01 02', 'YYYY---- --- --MM-DD') FROM dual
> > 2018-01-01 00:00:00 -10:00
> > (length of last spaces/separators group is 3)
> >
> > # SELECT to_timestamp('2018- -01 02', 'YYYY---- -- ---MM-DD') FROM dual
> > 02.01.2018 00:00:00
> > (length of last spaces/separators group is 2)
>
> Ooops... I'm sorry, but I've posted wrong results here. Correct
> version is here.
>
> # SELECT to_timestamp('2018- -01 02', 'YYYY---- --- --MM-DD') FROM dual
> ORA-01843: not a valid month
> (length of last spaces/separators group is 2)
>
> # SELECT to_timestamp('2018- -01 02', 'YYYY---- -- ---MM-DD') FROM dual
> 02.01.2018 00:00:00
> (length of last spaces/separators group is 3)
>
> So length of last group of spaces/separators in the pattern should be
> greater or equal to length of spaces/separators in the input string.
> Other previous groups are ignored in Oracle. And that seems
> ridiculous for me.

BTW, I've also revised documentation and regression tests. Patch is attached.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

Attachment Content-Type Size
0001-to-timestamp-format-checking-v15.patch application/octet-stream 16.9 KB

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