Overview

Overview

Pivotal Greenplum Command Center is a management tool for the Greenplum Big Data Platform. This section introduces key concepts about Greenplum Command Center and its components.

Introduction

Greenplum Command Center monitors system performance metrics, analyzes system health, and allows administrators 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 may be installed on a web server on the master host. Users view and interact with the collected Greenplum system data through this application.

Greenplum Command Center is comprised of data collection agents that run on the master host and each segment host. 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. You can access the data stored in the Greenplum Command Center database through the Greenplum Command Center Console and through SQL queries.

Note: Command Center requires Greenplum Database to operate because Command Center stores its information in a Greenplum database.

Supported Greenplum Platforms

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 Alliance:
  • Greenplum Database Module
  • Greenplum Data Integration Accelerator (DIA) Module
  • Greenplum Data Computing Appliance Hardware
Greenplum Database (software-only environments):
  • Greenplum Database

See the Release Notes for your Greenplum Command Center release for information about the supported software and hardware versions.

Architecture

The following figure illustrates the Greenplum Command Center architecture.

Greenplum Data Collection Agents

You can enable or disable Command Center using the gp_enable_gpperfmon server configuration parameter. After it is enabled, data collection agents run on all Greenplum hosts (master and segments), and start and stop along with Greenplum Database server processes.

The master agent polls all segment agents for system metrics and other data at a configurable interval (called the quantum). The master agent amasses 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 system data. Your Greenplum installation includes setup scripts to install the Command Center database (gpperfmon).

When this document refers to the Command Center database, it is referring to the database named gpperfmon.

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 the Command Center database accesses them via external tables. The history tables are regular database tables stored within the Command Center (gpperfmon) database. See Command Center Database Reference for the schema definitions of these tables.

Greenplum Command Center Console

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

Database administrative controls
  • Ability to stop/start the database
  • Ability to recover/rebalance segments
An interactive view of system metrics
  • Realtime
  • Historic (configurable by time)
An interactive view of system hardware health
  • This functionality is only available for Greenplum Data Computing Appliance environments.
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.
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.

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. For more information, see Installing the Greenplum Command Center Console.

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 http://www.lighttpd.net/.

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, as described in Web Server Administration.