Re: Horizontal scalability/sharding
От | Amit Kapila |
---|---|
Тема | Re: Horizontal scalability/sharding |
Дата | |
Msg-id | CAA4eK1KNNbn+a8DM+6FBSjV5J3cjb4e3uE2iGDOuqqqzvnaSMg@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: Horizontal scalability/sharding (Pavan Deolasee <pavan.deolasee@gmail.com>) |
Ответы |
Re: Horizontal scalability/sharding
|
Список | pgsql-hackers |
On Wed, Sep 2, 2015 at 4:19 PM, Pavan Deolasee <pavan.deolasee@gmail.com> wrote:
> On Wed, Sep 2, 2015 at 3:55 PM, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> wrote:
>>
>> On 2015-09-02 PM 06:41, Amit Langote wrote:
>>
>> Which, I now realize, is not the worry Amit Kapila's expresses.
>>
>> The deadlock was *indeed detected* in this case, with all the locks in the
>> same PG instance. In a sharded environment with multiple PG instances,
>> that becomes tricky. DLM (distributed lock manager/deadlock detector)
>> seems indeed necessary as Amit K. suspects.
>>
>
> Right. XC/XL did not address this issue and they rely on statement timeouts to break distributed deadlocks.
>
I think that will be difficult for application to decide and then it
> On Wed, Sep 2, 2015 at 3:55 PM, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> wrote:
>>
>> On 2015-09-02 PM 06:41, Amit Langote wrote:
>>
>> Which, I now realize, is not the worry Amit Kapila's expresses.
>>
>> The deadlock was *indeed detected* in this case, with all the locks in the
>> same PG instance. In a sharded environment with multiple PG instances,
>> that becomes tricky. DLM (distributed lock manager/deadlock detector)
>> seems indeed necessary as Amit K. suspects.
>>
>
> Right. XC/XL did not address this issue and they rely on statement timeouts to break distributed deadlocks.
>
I think that will be difficult for application to decide and then it
needs to decide the same for all statements which is tricky because
different statements could take different time. I think it is better to
have solution for this problem and deadlock should be detected.
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