Re: timestamp precision

Поиск
Список
Период
Сортировка
От A Gilmore
Тема Re: timestamp precision
Дата
Msg-id 4145CB3E.4040208@shaw.ca
обсуждение исходный текст
Ответ на Re: timestamp precision  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-novice
Tom Lane wrote:
> Michael Glaesemann <grzm@myrealbox.com> writes:
>
>>On Sep 13, 2004, at 4:19 PM, A Gilmore wrote:
>>
>>>Im using the default precision for my timestamps, 6.  Is it safe to
>>>declare this column unique?
>
>
>>If you are assuming it's unique because of the high precision, well,
>>you might get lucky, and you might not. (Some might even argue that
>>it's for all intents and purposes unique).
>
>
> I think what he's wondering is whether every two transactions will get
> distinguishable values of now(), so that putting a UNIQUE constraint on
> timestamps inserted by distinct transactions could never fail.
>
> I think this is an unsafe assumption, because:
>

Yeah, thats what I was meaning.  I didn't think it would work (by work,
I mean no chance of failure due to duplicate) but was hoping to be suprised.

Thank you for the insight.

A Gilmore

В списке pgsql-novice по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: LockAcquire: lock table 1 is out of memory
Следующее
От: Greg Donald
Дата:
Сообщение: nextval() clarification