I try to create PostgreSQL replication slot by the next command:

DO $$
BEGIN

IF NOT EXISTS (SELECT 1 FROM pg_catalog.pg_publication WHERE pubname = 'trade_events_pub') 
THEN

    CREATE PUBLICATION trade_events_pub FOR TABLE 
        public.trade_events;

END IF;

IF NOT EXISTS (SELECT 1 from pg_catalog.pg_replication_slots WHERE slot_name = 'trade_events_slot') 
THEN

    PERFORM pg_create_logical_replication_slot('trade_events_slot', 'pgoutput');

END IF;
END;

$$ LANGUAGE plpgsql;

I get the error:

[25001] ERROR: cannot create logical replication slot in transaction that has performed writes Where: SQL statement “SELECT pg_create_logical_replication_slot(‘trade_events_slot’, ‘pgoutput’)” PL/pgSQL function inline_code_block line 15 at PERFORM

If I try to run command CREATE PUBLICATION and PERFORM pg_create_logical_replication_slot in separate transactions it works fine.

I use PostgreSQL 15.3