Re: Clarifying "timestamp with time zone" - Mailing list pgsql-general

From Tom Lane
Subject Re: Clarifying "timestamp with time zone"
Date
Msg-id 315.1529091794@sss.pgh.pa.us
Whole thread Raw
In response to Clarifying "timestamp with time zone"  (Jeremy Finzel <finzelj@gmail.com>)
List pgsql-general
Jeremy Finzel <finzelj@gmail.com> writes:
> We often prefer to use timestamptz or "timestamp with time zone" in our
> environment because of its actually storing "objective time" with respect
> to UTC.  But in my own work experience, I have scarcely encountered a case
> where business users, and software engineers, do not actually think it
> means the opposite.

Yeah, it's confusing :-(.

> I do believe this is part of the SQL standard,

Actually not, or at least the standard thinks the type should behave
differently from this.  They think it should store a local timestamp and
then separately a GMT offset.  The way it works in PG was dreamed up ~20
years ago by Tom Lockhart, and in retrospect it was not a great idea
for him to have used the SQL-standard type name for something with
not-SQL-standard behavior.

However, at this point, it's not clear how we could change it without
causing truly enormous backwards-compatibility pain.  If it were a
fringe-usage type, maybe we could get away with a renaming, but it's
certainly not that.

> So it seems to me that "timestamp with time zone" is a misnomer in a big
> way, and perhaps it's worth at least clarifying the docs about this,

Don't the docs describe the behavior pretty clearly already?

            regards, tom lane


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