The gp_segment_configuration table contains information about mirroring and segment configuration.

Table 1. pg_catalog.gp_segment_configuration
column type references description
dbid smallint   The unique identifier of a segment (or master) instance.
content smallint   The content identifier for a segment instance. A primary segment instance and its corresponding mirror will always have the same content identifier.

For a segment the value is from 0-N, where N is the number of primary segments in the system.

For the master, the value is always -1.

role char   The role that a segment is currently running as. Values are p (primary) or m (mirror).
preferred_role char   The role that a segment was originally assigned at initialization time. Values are p (primary) or m (mirror).
mode char   The synchronization status of a segment with its mirror copy. Values are s (synchronized), c (change logging), or r (resyncing).
status char   The fault status of a segment. Values are u (up) or d (down).
port integer   The TCP port the database server listener process is using.
hostname text   The hostname of a segment host.
address text   The hostname used to access a particular segment on a segment host. This value may be the same as hostname in systems upgraded from 3.x or on systems that do not have per-interface hostnames configured.
replication_port integer   The TCP port the file block replication process is using to keep primary and mirror segments synchronized.
san_mounts int2vector gp_san_ configuration.oid An array of references to the gp_san_configuration table. Only used on systems that were initialized using sharred storage.