The maximum number of concurrent connections to the database server. In a Greenplum Database system, user client connections go through the Greenplum master instance only. Segment instances should allow 5-10 times the amount as the master. When you increase this parameter, max_prepared_transactions must be increased as well. For more information about limiting concurrent connections, see "Configuring Client Authentication" in the Greenplum Database Administrator Guide.

Increasing this parameter may cause Greenplum Database to request more shared memory.Increasing this parameter might cause Greenplum Database to request more shared memory. See shared_buffers for information about Greenplum server instance shared memory buffers.