Configuration Parameter Categories

The gadget spec URL could not be found
These parameters control how clients connect and authenticate to Greenplum Database.
The gadget spec URL could not be found
  1.  Connection and Authentication Parameters
  2.  System Resource Consumption Parameters
  3.  Query Tuning Parameters
  4.  Error Reporting and Logging Parameters
  5.  System Monitoring Parameters
  6.  Runtime Statistics Collection Parameters
  7.  Automatic Statistics Collection Parameters
  8.  Client Connection Default Parameters
  9.  Lock Management Parameters
  10.  Workload Management Parameters
  11.  External Table Parameters
  12.  Past PostgreSQL Version Compatibility Parameters
  13.  Greenplum Array Configuration Parameters
The gadget spec URL could not be found

You can use pgoptions to set the configuration parameter.

Connect to the master in utility mode to do catalog maintenance. For example:
$ PGOPTIONS='-c gp_session_role=utility' psql template1

$ PGOPTIONS='-c gp_session_role=utility' psql template1

Uploading Configuration File Changes Only
  1. The gpstop utility can upload changes to the pg_hba.conf configuration file and to runtime parameters in the master postgresql.conf file without service interruption. 
  2. Active sessions pick up changes when they reconnect to the database. 
  3. Many server configuration parameters require a full system restart (gpstop -r) to activate. For information about server configuration parameters, see the Greenplum Database Reference Guide.
To upload runtime configuration file changes without restarting
$ gpstop -u

see also gpconfig
The gadget spec URL could not be found