Re: Distributed systems and primary keys

On Fri, Jul 12, 2013 at 10:04 AM, Koichi Suzuki <koichi(dot)szk(at)gmail(dot)com>wrote:

> 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
>

Thanks Koichi. I will be looking into it shortly.

Melvin

>
>
> 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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>
>