Re: Copy function for logical replication slots

On Thu, Jun 28, 2018 at 7:10 PM, Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> On Thu, Jun 28, 2018 at 5:37 PM, Peter Eisentraut
> <peter.eisentraut@2ndquadrant.com> wrote:
>> On 6/28/18 08:47, Michael Paquier wrote:
>>>>> There could be some cases where
>>>>> copying a physical slot also makes sense.
>>>> I've thought that but I didn't find concrete use case. That's why I
>>>> started with only logical slot.
>>> Let's imagine the case of a single base backup which is associated to a
>>> given replication slot, and that this backup is then used to spawn
>>> multiple standbys where each one of them needs a separate slot to
>>> consume changes at their pace.  If you can copy the slot used in the
>>> first backup, then both nodes could consume it.  That looks useful to
>>> me to make sure that both slots are based a consistent point.
>>
>
> Thank you, that sounds useful. I'll update the patch to include physical slots.
>
>> I think this use case of cloning replicas would also be interesting in
>> the logical slot case.
>>
>
> +1
>

Attached an updated patch including copy function support for logical
slots as well as physical slots. Please review it.

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center