In order to effectively manage a replication cluster, ltcluster needs to store
information about the servers in the cluster in a dedicated database schema.
This schema is automatically created by the ltcluster extension, which is installed
during the first step in initializing a ltcluster-administered cluster
(ltcluster primary register
)
and contains the following objects:
ltcluster.events
: records events of interestltcluster.nodes
: connection and status information for each server in the
replication clusterltcluster.monitoring_history
: historical standby monitoring information
written by ltclusterd
ltcluster.nodes
, additionally showing the
name of the server's upstream node
The ltcluster metadata schema can be stored in an existing database or in its own dedicated database. Note that the ltcluster metadata schema cannot reside on a database server which is not part of the replication cluster managed by ltcluster.
A database user must be available for ltcluster to access this database and perform
necessary changes. This user does not need to be a superuser, however some operations
such as initial installation of the ltcluster extension will require a superuser
connection (this can be specified where required with the command line option
--superuser
).