Re: Regarding TZ conversion

Thanks for the clarification.

Is it advisable to modify the Default? Will it override when we apply a
patch or upgrade the DB?

What about creating a new file like below and update the postgres.conf with
the new name.

# New tz offset
@INCLUDE Default

@OVERRDIE
IST 19800
........................

*Regards,*
*Rajin *

On Thu, Jun 4, 2020 at 7:23 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Rajin Raj <rajin(dot)raj(at)opsveda(dot)com> writes:
> > Option 1: <some_date with tz> AT TIME ZONE 'IST'
> > Option 2: <some_date with tz> AT TIME ZONE 'Asia/Kolkata'
> > In the first option, I get +2:00:00 offset (when *timezone_abbrevations =
> > 'Default'*) and for option 2 , +5:30 offset.
>
> > I can see multiple entries for IST in pg_timezone_names with
> > different utc_offset, but in pg_timezone_abbrev there is one entry. I
> guess
> > AT TIME ZONE function using the offset shown in pg_timezone_abbrev.
>
> No. If you use an abbreviation rather than a spelled-out zone name,
> you get whatever the timezone_abbrevations file says, which by default
> is
>
> $ grep IST .../postgresql/share/timezonesets/Default
> # CONFLICT! IST is not unique
> # - IST: Irish Standard Time (Europe)
> # - IST: Indian Standard Time (Asia)
> IST 7200 # Israel Standard Time
>
> If that's not what you want, change it. See
>
> https://www.postgresql.org/docs/current/datetime-config-files.html
>
> and also
>
>
> https://www.postgresql.org/docs/current/datatype-datetime.html#DATATYPE-TIMEZONES
>
> regards, tom lane
>