PostgreSQL – Fix ‘pg_ctl: Server Did Not Promote in Time’ Error

postgresql

I setup a two node postgresql 10 cluster to test replication. Following this guide

I was able to get replication running correctly. However, I want to test the process of the slave to master. When I stop the master node, and run pg_ctl promote -D on the slave, I get:

pg_ctl: server did not promote in time

I've looked online and can't find anything related to being unable to promote in time. After running the command and receiving the error, I have to manually start postgresql and it is still running in a read only state.

Postgresql is running on Ubuntu 18.04.

Best Answer

To promote, pg_ctl writes a file called $PGDATA/promote, sends SIGUSR1, then waits a default of 60 seconds for the server to acknowledge that it is now read-write. Does that file exist? What is in the server log file?

Related Solutions

Postgresql – About “pg_ctl promote” of PostgreSQL9.1

There is no 'demote' option for pg_ctl - if the primary was cold when the standby was promoted perhaps it could be converted to a standby manually, but otherwise it will need a new base backup from the new primary.

The normal reason for switchover would be if the primary has failed so this would not be necessary.

Postgresql – Taking hot backup of slave node in postgres (master-slave config with repmgr)

At least on 9.3, you can run pg_basebackup against a hot standby replica, and that's the approach I would recommend. To do this, you must have postgresql.conf set appropriately:

max_wal_senders = 2
hot_standby = on

You didn't specify your version. If you're on a version that can't do a pg_basebackup from a standby you're pretty much out of luck - you need to do a logical dump, dump from the master, or stop the replica for the backup.

Best Answer

Related Solutions

Postgresql – About “pg_ctl promote” of PostgreSQL9.1

Postgresql – Taking hot backup of slave node in postgres (master-slave config with repmgr)

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