Greenplum Command Center

About Command Center
Greenplum Command Center is a management tool for the Greenplum Big Data Platform. Greenplum Command Center monitors system performance metrics, system health, and also provides administrators the ability to perform management tasks such as start, stop, and recovery of systems in a Greenplum environment. 

The Greenplum Command Center Console is an interactive graphical web application that can optionally be installed on a web server on the master host, and used to view and interact with the collected Command Center data.

Greenplum Command Center is comprised of data collection agents that run on the master host and each segment host (either Greenplum Hadoop or Greenplum Database hosts). The agents collect data about queries and system utilization and send it to the Greenplum master host at regular intervals. 

Greenplum Command Center stores its data and metrics in a dedicated Greenplum database (the Command Center database) whose information is distributed among the master host and segment hosts, like any other Greenplum Database. The data stored in the Greenplum Command Center database can be accessed through the Greenplum Command Center Console or through SQL queries.

Note: Because Command Center stores its information in a Greenplum database, Greenplum Database is a requirement for running Command Center.

Greenplum Command Center is currently certified for the Greenplum Data Computing Appliance (DCA) and Greenplum Database software-only environments. Command Center monitors the following for each environment:
  • Greenplum Data Computing Appliance
  • Greenplum Database Module
  • Greenplum Hadoop Module
  • Greenplum Data Integration Accelerator (DIA) Module
  • Greenplum Database (software-only environments)
  • Greenplum Database (4.0 and higher supported, 4.2.1 or higher recommended)

Greenplum Command Center Agents
Command Center can be enabled or disabled using the gp_enable_gpperfmon server configuration parameter. Once enabled, the Greenplum Command Center data collection agents run on all Greenplum hosts (master and segments), and are started and stopped along with the Greenplum Database server processes.
The master agent polls all segment agents for system metrics and other data at a configurable interval (known as the quantum). The master agent pulls together the data from all segments, stores it in flat files, and periodically commits the data in the files to the Greenplum Command Center database.

Greenplum Command Center Database
The Greenplum Command Center database (gpperfmon) is a database within your Greenplum system dedicated to storing and serving performance data. Your Greenplum installation includes setup scripts to install the gpperfmon database. Greenplum administrators can connect to the Command Center database using client programs such as psql or application programming interfaces (APIs) such as JDBC (Java Database Connectivity) and ODBC (Open Database Connectivity). 

Administrators can also use the Greenplum Command Center Console to view reports on current and historical performance and perform other managment tasks.

The Command Center database consists of three sets of tables; now tables store data on current system metrics such as active queries, history tables store data on historical metrics, and tail tables are for data in transition. Tail tables are for internal use only and should not be queried by users. The now and tail data are stored as text files on the master host file system, and accessed by the Command Center database via external tables. The history tables are regular database tables stored within the Command Center (gpperfmon) database.

Greenplum Command Center Console
Greenplum Command Center provides a graphical console for viewing performance metrics and performing other database administrative tasks. This browser-based application provides the following functionality:

1. Database administrative Controls
  • Ability to stop/start the database
  • Ability to recover / rebalance segments
2. An interactive View of System Metrics
  • Realtime
  • Historic (configurable by time)
3. An Interactive View of System Health
  • Hardware health
  • Software Health (Greenplum HD and Greenplum Database)
4. Database Query Monitoring
  • Ability to view, search, prioritize, or cancel any query in the system.
  • Ability to view the internals of any query, including the query plan, query plan iterator-level details, and real-time information about individual scans and joins.
5. Database Workload Management
  • Ability to configure resource queues
  • Ability to prioritize users

If you have multiple Greenplum environments, you can create separate Command Center instances for them. Each separate console instance operates on a unique port and has its own unique configuration options.

Greenplum Command Center Web Service
The Greenplum Command Center Console queries the Command Center database through a web service framework composed of a lightweight lighttpd web server and Python-based middleware. The lighttpd server is an open-source web server with a low memory footprint and light CPU load. For more information, see

The console setup utility sets up the lighttpd web server and web service, prompting you for basic configuration information on the desired port and SSL options. Under normal conditions, the web server and web service API require minimal maintenance and administration.

The table below displays the limitations of Greenplum Command Center 1.2 when using a Greenplum Database other than 4.2.1 

Greenplum Command Center 1.2 limitations by Greenplum Database

 Cancel Query
The ability to cancel a query from the
Query Monitor tab
 Not Supported  Not Supported  Not Supported 
 Storage Monitoring
The Storage Monitoring section of the
Administration tab
 Not Supported Not Supported Not Supported
 Query Priority
The priority of the query displays in a
column on the Query Monitor tab
Supported for
running queries.
Not supported
for queued
 Supported for
running queries.
Not supported
for queued
  Supported for
running queries.
Not supported
for queued
 Set Query Priority
The ability to change the priority of a
query by using the drop-down menu in
the Priority column on the Query Monitor
 Supported for
running queries.
Not supported
for queued
 Supported for
running queries.
Not supported
for queued
 Supported for
running queries.
Not supported
for queued
The ability to rebalance a recovered
segment from the Segment Health
section of the Administration tab.
 Supported Supported You need to
restart the
Database before
you rebalance a
segment. You
are prompted to
do this in the UI.

Table 4 Greenplum Command Center 1.2 Documentation

Title Part Number Revision
Greenplum Command Center 1.2 Administrator Guide 300-012-844 A01
Greenplum Command Center Release Notes 300-013-xxx A01

See also

Setting Up Greenplum Command Center
Administering Command Center
Command Center Utility Reference
Command Center Configuration File Reference
Command Center Database Reference
Command Center FAQ