Re: Distributed systems and primary keys

In Postgres-XC, GTM assigns sequence value to all the transactions in its
cluster. XC is a kind of tightly-coupled distributed system. In a
loosely-coupled distributed system, where each database is autonomous, we
may need another mechanism.

I've learned that logical replication (used to be bi-directional
replication) people are doing this kind of work.

Regards;

----------
Koichi Suzuki

2013/7/12 Joshua D. Drake <jd(at)commandprompt(dot)com>

>
> On 07/12/2013 07:23 AM, Melvin Call wrote:
>
>> Hello list,
>>
>> Can anyone point me to some reading material on how auto-generated
>> sequence primary keys are handled on distributed systems? I think the
>> advice used to be to use GUIDs, but I thought I read somewhere that
>> PostgreSQL now assigns a pool of numbers to each node when a sequence is
>> implemented. I have searched the PostgreSQL 9.1.5 Documentation, but
>> apparently my search terms are not quite what it takes, or dreamt that up.
>>
>
> PostgreSQL itself does not support a distributed architecture. You may be
> thinking of Postgres-XC?
>
> Sequences are local to each instances and it is not a pool, it is a 64bit
> allocation for each sequence within the local node, generally constrained
> only when called from the serial (big serial being 64 bits) type to 32 bits.
>
> Sincerely,
>
> Joshua D. Drake
>
>
>
>
>> Thanks,
>> Melvin
>>
>
>
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