pg_timezone_names

Started by PG Bug reporting formabout 8 years ago2 messagesdocs
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#1PG Bug reporting form
noreply@postgresql.org

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/9.1/static/view-pg-timezone-names.html
Description:

We are exporting data from postgres into another "all in one" data store,
and i had a quick question regarding the time offsets. The UTC_OFFSET, does
it change when IS_DST is true/false? Or do I need to take the UTC_OFFSET
interval and then possibly add 1 more if IS_DST is true? Example: 1/1/2018
not in DST, interval says -10. On 3/1/2018, IS_DST turns to TRUE. Will the
interval now say -9, or do i need to take the -10 and substract 1 to get to
-9?

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: PG Bug reporting form (#1)
Re: pg_timezone_names

=?utf-8?q?PG_Doc_comments_form?= <noreply@postgresql.org> writes:

We are exporting data from postgres into another "all in one" data store,
and i had a quick question regarding the time offsets. The UTC_OFFSET, does
it change when IS_DST is true/false?

Yes; utc_offset reflects the zone's current offset from UTC, so it changes
with the seasons if the zone has DST laws.

Or do I need to take the UTC_OFFSET
interval and then possibly add 1 more if IS_DST is true?

Prepare to be disappointed; you can't assume it works like that.
See the thread starting here:

http://mm.icann.org/pipermail/tz/2017-December/025682.html

You haven't said what it is you are hoping to accomplish, so it's
hard to say if there's some safer way to do it.

regards, tom lane