Re: In logical replication concurrent update of partition key creates a duplicate record on standby.

On Wed, Feb 7, 2018 at 6:00 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Wed, Feb 7, 2018 at 3:42 PM, amul sul <sulamul(at)gmail(dot)com> wrote:
>> On Wed, Feb 7, 2018 at 3:03 PM, Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com> wrote:
>>> On 7 February 2018 at 13:53, amul sul <sulamul(at)gmail(dot)com> wrote:
>>>> Hi,
>>>>
>>>> If an update of partition key involves tuple movement from one partition to
>>>> another partition then there will be a separate delete on one partition and
>>>> insert on the other partition made.
>>>>
>>>> In the logical replication if an update performed on the master and standby at
>>>> the same moment, then replication worker tries to replicate delete + insert
>>>> operation on standby. While replying master changes on standby for the delete
>>>> operation worker will log "concurrent update, retrying" message (because the
>>>> update on standby has already deleted) and move forward to reply the next
>>>> insert operation. Standby update also did the same delete+insert is as part of
>>>> the update of partition key in a result there will be two records inserted on
>>>> standby.
>>>
>>> A quick thinking on how to resolve this makes me wonder if we can
>>> manage to pass some information through logical decoding that the
>>> delete is part of a partition key update. This is analogous to how we
>>> set some information locally in the tuple by setting
>>> tp.t_data->t_ctid.ip_blkid to InvalidBlockNumber.
>>>
>>
>> +1,
>>
>
> I also mentioned the same thing in the other thread [1], but I think
> that alone won't solve the dual record problem as you are seeing. I
> think we need to do something for next insert as you are suggesting.
>

Can you please once check what was the behavior before Update Tuple
routing patch (Commit-id: 2f178441) went in?

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com