Re: Why is time with timezone 12 bytes?

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От Tom Lane
Тема Re: Why is time with timezone 12 bytes?
Дата
Msg-id 2683.1285192623@sss.pgh.pa.us
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Ответ на Why is time with timezone 12 bytes?  (Josh Berkus <josh@agliodbs.com>)
Ответы Re: Why is time with timezone 12 bytes?  (Josh Berkus <josh@agliodbs.com>)
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Josh Berkus <josh@agliodbs.com> writes:
> I was just checking on our year-2027 compliance, and happened to notice
> that time with time zone takes up 12 bytes.  This seems peculiar, given
> that timestamp with time zone is only 8 bytes, and at my count we only
> need 5 for the time with microsecond precision.  What's up with that?

I think it's an 8-byte seconds count plus 4 bytes to indicate the
timezone.  If this datatype had any actual real-world use then it might
be worth worrying about how big it is, but AFAICS its only excuse for
existence is to satisfy the SQL standard.

> Also, what is the real range of our 8-byte *integer* timestamp?

See the fine manual.  I believe the limits have more to do with
calendar arithmetic than with the nominal range of 2^64 microseconds.
        regards, tom lane


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