Re: [GENERAL] looking for a globally unique row ID

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От George Neuner
Тема Re: [GENERAL] looking for a globally unique row ID
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Msg-id f3fmrc5hr9t73otbqdgq9g98r8ahhhhkpk@4ax.com
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Ответ на [GENERAL] looking for a globally unique row ID  (Rafal Pietrak <rafal@ztk-rp.eu>)
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On Thu, 14 Sep 2017 17:02:05 -0500, Merlin Moncure
<mmoncure@gmail.com> wrote:

>... With sequences, the database *guarantees* that the
>identifier is unique with no exceptions; there never will be a unique
>value.  Can you give a hypothetical example of how you think they
>wouldn't work?

Jumping in here, but a month or so past someone here was complaining
about a restore resetting all the sequences in the database. Obviously
a strange situation [I've never seen it], but something to worry about
if you are relying on sequences for uniqueness.

Upthread I suggested the timestamp+counter approach.  I wasn't
thinking about this issue specifically, but it is immune to the
counter being reset [accidentally or otherwise].

George



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