Re: Logical archiving

On Fri, 4 Dec 2020 at 14:36, Andrey Borodin <x4mmm(at)yandex-team(dot)ru> wrote:

> >
> > The most time consuming process is logical decoding, mainly due to long
> running transactions.
> Currently I do not experience problem of high CPU utilisation.
>
> I'm wondering why the LSN isn't moving fast enough for your use case.

> > In order to minimize your issue, we should improve the logical decoding
> mechanism.
> No, the issue I'm facing comes from the fact that corner cases of failover
> are not solved properly for logical replication. Timelines, partial
> segments, archiving along with streaming, starting from arbitrary LSN
> (within available WAL), rewind, named restore points, cascade replication
> etc etc. All these nice things are there for WAL and are missing for LR.
> I'm just trying to find shortest path through this to make CDC(changed data
> capture) work.
>
> Craig started a thread a few days ago [1] that described some of these
issues and possible solutions [2]. The lack of HA with logical replication
reduces the number of solutions that could possibly use this technology.
Some of the facilities such as logical replication slots and replication
origin on failover-candidate subscribers should encourage users to adopt
such solutions.

[1]
https://www.postgresql.org/message-id/CAGRY4nx0-ZVnFJV5749QCqwmqBMkjQpcFkYY56a9U6Vf%2Bf7-7Q%40mail.gmail.com
[2]
https://wiki.postgresql.org/wiki/Logical_replication_and_physical_standby_failover

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