Enabling Synchronization Replication with the Log-Based Method v6.2

This section applies only to Postgres database servers of version 9.4 and later. If you plan to use the log-based method of synchronization replication with any publication database running under the Postgres database server, the following configuration parameter settings are required in the configuration file, postgresql.conf, of the Postgres database server:

• wal_level. Set to logical.
• max_wal_senders. Specifies the maximum number of concurrent connections (that is, the maximum number of simultaneously running WAL sender processes). Set at minimum, to the number of SMR publication databases on this database server that will use the log-based method. In addition, if MMR primary nodes are to run on this database server, also add the number of MMR primary nodes that will use the log-based method.
• max_replication_slots. Specifies the maximum number of replication slots. Set at minimum, to the number of SMR publication databases on this database server that will use the log-based method. In addition, if MMR primary nodes are to run on this database server with the log-based method, see Replication Origin for information on the additional number of replication slots required.

See Synchronization Replication with the Log-Based Method for information on the log-based method of synchronization replication.

The Postgres database server must be restarted after altering any of these configuration parameters.

In addition, the pg_hba.conf file requires an entry for each publication database user of publication databases that are to use the log-based method. Such database users must be included as a replication database user in the pg_hba.conf file. See Postgres Server Authentication for additional information.