Waiting for PostgreSQL 19 – Sequence synchronization in logical replication.

First, on 9th of October 2025, Amit Kapila committed patch:

Add "ALL SEQUENCES" support to publications.
 
This patch adds support for the ALL SEQUENCES clause in publications,
enabling synchronization/replication of all sequences that is useful for
upgrades.
 
Publications can now include all sequences via FOR ALL SEQUENCES.
psql enhancements:
\d shows publications for a given sequence.
\dRp indicates if a publication includes all sequences.
 
ALL SEQUENCES can be combined with ALL TABLES, but not with other options
like TABLE or TABLES IN SCHEMA. We can extend support for more granular
clauses in future.
 
The view pg_publication_sequences provides information about the mapping
between publications and sequences.
 
This patch enables publishing of sequences; subscriber-side support will
be added in upcoming patches.
 
Author: vignesh C <vignesh21@gmail.com>
Author: Tomas Vondra <tomas@vondra.me>
Reviewed-by: shveta malik <shveta.malik@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Nisha Moond <nisha.moond412@gmail.com>
Reviewed-by: Shlok Kyal <shlok.kyal.oss@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Discussion: https://postgr.es/m/CAA4eK1LC+KJiAkSrpE_NwvNdidw9F2os7GERUeSxSKv71gXysQ@mail.gmail.com

And then, on 5th of November 2025, he also committed patch:

Add sequence synchronization for logical replication.
 
This patch introduces sequence synchronization. Sequences that are synced
will have 2 states:
   - INIT (needs [re]synchronizing)
   - READY (is already synchronized)
 
A new sequencesync worker is launched as needed to synchronize sequences.
A single sequencesync worker is responsible for synchronizing all
sequences. It begins by retrieving the list of sequences that are flagged
for synchronization, i.e., those in the INIT state. These sequences are
then processed in batches, allowing multiple entries to be synchronized
within a single transaction. The worker fetches the current sequence
values and page LSNs from the remote publisher, updates the corresponding
sequences on the local subscriber, and finally marks each sequence as
READY upon successful synchronization.
 
Sequence synchronization occurs in 3 places:
1) CREATE SUBSCRIPTION
    - The command syntax remains unchanged.
    - The subscriber retrieves sequences associated with publications.
    - Published sequences are added to pg_subscription_rel with INIT
      state.
    - Initiate the sequencesync worker to synchronize all sequences.
 
2) ALTER SUBSCRIPTION ... REFRESH PUBLICATION
    - The command syntax remains unchanged.
    - Dropped published sequences are removed from pg_subscription_rel.
    - Newly published sequences are added to pg_subscription_rel with INIT
      state.
    - Initiate the sequencesync worker to synchronize only newly added
      sequences.
 
3) ALTER SUBSCRIPTION ... REFRESH SEQUENCES
    - A new command introduced for PG19 by f0b3573c3a.
    - All sequences in pg_subscription_rel are reset to INIT state.
    - Initiate the sequencesync worker to synchronize all sequences.
    - Unlike "ALTER SUBSCRIPTION ... REFRESH PUBLICATION" command,
      addition and removal of missing sequences will not be done in this
      case.
 
Author: Vignesh C <vignesh21@gmail.com>
Reviewed-by: shveta malik <shveta.malik@gmail.com>
Reviewed-by: Hou Zhijie <houzj.fnst@fujitsu.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Nisha Moond <nisha.moond412@gmail.com>
Reviewed-by: Shlok Kyal <shlok.kyal.oss@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAA4eK1LC+KJiAkSrpE_NwvNdidw9F2os7GERUeSxSKv71gXysQ@mail.gmail.com

Continue reading Waiting for PostgreSQL 19 – Sequence synchronization in logical replication.

Waiting for PostgreSQL 10 – Identity columns

On 6th of April 2017, Peter Eisentraut committed patch:

Identity columns
 
This is the SQL standard-conforming variant of PostgreSQL's serial
columns.  It fixes a few usability issues that serial columns have:
 
- CREATE TABLE / LIKE copies default but refers to same sequence
- cannot add/drop serialness with ALTER TABLE
- dropping default does not drop sequence
- need to grant separate privileges to sequence
- other slight weirdnesses because serial is some kind of special macro

Continue reading Waiting for PostgreSQL 10 – Identity columns

Waiting for PostgreSQL 10 – Add pg_sequence system catalog

On 20th of December, Peter Eisentraut committed patch:

Add pg_sequence system catalog
 
Move sequence metadata (start, increment, etc.) into a proper system
catalog instead of storing it in the sequence heap object.  This
separates the metadata from the sequence data.  Sequence metadata is now
operated on transactionally by DDL commands, whereas previously
rollbacks of sequence-related DDL commands would be ignored.
 
Reviewed-by: Andreas Karlsson

Continue reading Waiting for PostgreSQL 10 – Add pg_sequence system catalog

Tips N’ Tricks – setting field based on order

Let's imagine following situation:

create table test (id int4 primary key, priority int4);
insert into test (id)
    select distinct (random() * 100000000)::int4 from generate_series(1,1000);

Table test will now contain some (up to 1000) records, with random ids.

Now, we want to update first 3 records (ordered by id) to have following values in priority:

  1. 10000
  2. 5000
  3. 1000

Continue reading Tips N’ Tricks – setting field based on order

Waiting for 8.4 – partial-match support in GIN, and sequence restart

Today we have two interesting patches:

  • patch by Teodor Sigaev and Oleg Bartunov, and committed by Tom Lane, which adds interesting capability to GIN indexes
  • patch by Zoltan Boszormenyi, also committed by Tom, which adds “RESTART" option to ALTER SEQUENCE. With some interesting consequences

Continue reading Waiting for 8.4 – partial-match support in GIN, and sequence restart