Re: BUG #16472: Bug in to_timestamp ?

timezone = Asia/Taipei
version = PostgreSQL 9.6rc1, compiled by Visual C++ build 1800, 64-bit

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> 於 2020年6月2日 週二 上午12:18寫道：

> Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> writes:
> > On Mon, Jun 1, 2020 at 1:38 PM PG Bug reporting form
> > <noreply(at)postgresql(dot)org> wrote:
> >> I execute a update SQL as below :
> >> update Table1 set date1=to_timestamp('19790701000000',
> 'YYYYMMDDHH24MISS')
> >> where .....
> >> date1 is a timestamp type column, the result in DB is 1979-07-01
> 01:00:00
> >> where come from that '01' hour ?
>
> > It's likely related to clock shift in your timezone.
>
> July 1 would be an odd time for a seasonal DST shift ... but quickly
> thumbing through the tzdata files, I see one for Asia/Taipei on that date
> in 1979. So I guess that the OP is using that zone, and the answer to the
> question is "midnight of that date did not exist in Taiwan; their clocks
> shifted forward from 23:59:59 to 01:00:00".
>
> regards, tom lane
>