Re: logical decoding and replication of sequences, take 2 - Mailing list pgsql-hackers

From Christophe Pettus
Subject Re: logical decoding and replication of sequences, take 2
Date
Msg-id 29FD2D82-E3B7-4C62-B443-01800A5E78A0@thebuild.com
Whole thread Raw
In response to Re: logical decoding and replication of sequences, take 2  (Tomas Vondra <tomas.vondra@enterprisedb.com>)
Responses Re: logical decoding and replication of sequences, take 2
List pgsql-hackers
Hi,

I wanted to hop in here on one particular issue:

> On Dec 12, 2023, at 02:01, Tomas Vondra <tomas.vondra@enterprisedb.com> wrote:
> - desirability of the feature: Random IDs (UUIDs etc.) are likely a much
> better solution for distributed (esp. active-active) systems. But there
> are important use cases that are likely to keep using regular sequences
> (online upgrades of single-node instances, existing systems, ...).

+1.

Right now, the lack of sequence replication is a rather large foot-gun on logical replication upgrades.  Copying the
sequencesover during the cutover period is doable, of course, but: 

(a) There's no out-of-the-box tooling that does it, so everyone has to write some scripts just for that one function.
(b) It's one more thing that extends the cutover window.

I don't think it is a good idea to make it mandatory: for example, there's a strong use case for replicating a table
butnot a sequence associated with it.  But it's definitely a missing feature in logical replication. 


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