CODEWITHSUNDEEP
postgresqllogical-replicationpatroni
EXK
EXK

Reputation: 33

patroni - permanent logical replication slots - not working

I am trying to implement logical replication in a postgres cluster, where cluster switchover/failover is managed by patroni. I am trying to leverage the permanent replication slot feature. Using patroni version 2.1.1 on Postgres version 13.5. I have included my patroni config file below. After stopping and starting patroni, I notice that 2 physical replication slots called host_1 and host_2 are created even though patroni config defines implementation of logical replication. Patroni seems to be creating them by default.

postgres=# select * from pg_replication_slots;
 slot_name | plugin | slot_type | datoid | database | temporary | active | active_pid | xmin | catalog_xmin | restart_lsn | confirmed_flush_lsn | wal_status | safe_wal_size
-----------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+-------------+---------------------+------------+---------------
 host_2    |        | physical  |        |          | f         | t      |      23825 |      |              | B5/2602F808 |                     | reserved   |
 host_0    |        | physical  |        |          | f         | t      |      23838 |      |              | B5/2602F808 |                     | reserved   |
(2 rows)

#Patroni configuration
loop_wait: 10
master_start_timeout: 300
maximum_lag_on_failover: 1048576
postgresql:
  callbacks:
    on_role_change: /etc/patroni/patroni_callback.sh
    on_start: /etc/patroni/patroni_callback.sh
    on_stop: /etc/patroni/patroni_callback.sh
  parameters:
    archive_command: sh /etc/patroni/cfg/archive_command_pgbackrest.sh %p %f
    archive_mode: 'on'
    archive_timeout: 0
    config_file: /data/postgresql.conf
    hot_standby: 'on'
    log_directory: /log
    max_connections: 210
    max_locks_per_transaction: 64
    max_prepared_transactions: 0
    max_replication_slots: 10
    max_wal_senders: 10
    max_worker_processes: 4
    password_encryption: trust
    pg_stat_statements.max: 1000
    pg_stat_statements.track: top
    shared_preload_libraries: pg_stat_statements,pg_buffercache,pg_stat_kcache,wal2json
    track_commit_timestamp: false
    wal_keep_size: 11200
    wal_level: logical
    wal_log_hints: true
  recovery_conf:
    restore_command: sh /etc/patroni/cfg/restore_command_pgbackrest.sh %p %f
  slots:
    db_slot:
      database: driver_test
      plugin: wal2json
      type: logical
  use_pg_rewind: true
  use_slots: true
retry_timeout: 10
synchronous_mode: 'off'
synchronous_mode_strict: 'off'
ttl: 30

The only changes to the working patroni config was to change the following

slots:
    db_slot:
      database: driver_test
      plugin: wal2json
      type: logical
use_slots: true

Upvotes: 1

Views: 1358

Answers (2)

Mahesh Math
Mahesh Math

Reputation: 1

I suggest leave it to the patroni to manager. It automatically creates the slots. If we mention the slot them we might not be able to use same and we will end up in creating too many slots

Upvotes: 0

Fabrice Chapuis
Fabrice Chapuis

Reputation: 498

If the use_slots option is activated, Patroni will automatically create physical replication slots on the primary instance. The ignore_slots option has no impact on the physical replication slots, they are always present despite the use of this parameter. I don't no why!

postgresql:
   use_pg_rewind: true
   use_slots: true
retry_timeout: 10
slots:
   subscrip:
     database: db
     plugin: pgoutput
ignore_slots:
- name: slot1
   type: physical
- name: slot2
   type: physical

Upvotes: 0

Related Questions