The gp_id system catalog table identifies the Greenplum Database system name and number of segments for the system. It also has local values for the particular database instance (segment or master) on which the table resides. This table is defined in the pg_global tablespace, meaning it is globally shared across all databases in the system.
|gpname||name||The name of this Greenplum Database system.|
|numsegments||integer||The number of segments in the Greenplum Database system.|
|dbid||integer||The unique identifier of this segment (or master) instance.|
|content||integer||The ID for the portion of data on this segment instance. A primary and its
mirror will have the same content ID.
For a segment the value is from 0-N-1, where N is the number of segments in Greenplum Database.
For the master, the value is -1.