I came across this error by using repmgr5.4 for pg15, but the problem arose in pg_rewind, so I installed pg16 and tried again, the error persists like this:
$ /usr/pgsql-16/bin/pg_rewind -D '/pgdata' --source-server='host=172.17.1.2 port=5432 user=rep dbname=repmgr connect_timeout=5' pg_rewind: error: could not fetch remote file "global/pg_control": ERROR: permission denied for function pg_read_binary_file
Originally the server here at 172.17.0.2 was the primary and 172.17.1.2 was the standby replication server. I have created the user 'rep' with full replication privilege as described on page: https://www.postgresql.org/docs/16/app-pgrewind.html
CREATE EXTENSION repmgr;
GRANT pg_checkpoint TO rep;
GRANT pg_read_all_stats TO rep;
GRANT EXECUTE ON function pg_catalog.pg_ls_dir(text, boolean, boolean) TO rep;
GRANT EXECUTE ON function pg_catalog.pg_stat_file(text, boolean) TO rep;
GRANT EXECUTE ON function pg_catalog.pg_read_binary_file(text) TO rep;
GRANT EXECUTE ON function pg_catalog.pg_read_binary_file(text, bigint, bigint, boolean
And I have made it 'trust' among the intranet 172.17.0.0/16 in pg_hba.conf:
I used repmgr -h 172.17.0.2 -U rep -d repmgr standby clone to make the replica/standby on 172.17.1.2 and basically it called pg_basebackup to do the job. Checking the replication status from the old primary @172.17.0.2 with
SELECT * FROM pg_stat_replication; would return a table containing: state=streaming, sync_state=async
After that, I shut down the postgresql server on the old primary. And ordered `pg_ctl -w -D '/pgdata' promote` to turn it into the new primary.
After that is where the issue occured - the pg_rewind on the old primary won't function and threw out the error code.
