About Pivotal Greenplum Command Center
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.
Greenplum Command Center monitors system performance metrics, analyzes system health, and allows administrators to perform some management tasks in a Greenplum environment. The Greenplum Command Center Console is an interactive graphical web application that is installed on a web server, usually 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 update the Greenplum master host at regular intervals. Greenplum Command Center stores its data and metrics in a dedicated Greenplum database (the Command Center database, gpperfmon) whose information is distributed among the master host and segment hosts like any other Greenplum Database. You can access the data stored in the 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 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.
The following figure illustrates the Greenplum Command Center architecture.
Greenplum Data Collection Agents
Greenplum data collection agents run on Greenplum segment hosts to collect the query and system statistics to be displayed in the Command Center. The agents are installed with the Greenplum Database distribution but are not enabled until you create the Greenplum Command Center database (gpperfmon) and start them. The agents may also be enabled or disabled by setting the
gp_enable_gpperfmon server configuration parameter. When this parameter is enabled, the 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 Database installation includes the
gpperfmon_install utility to install the Command Center database and optionally start the data collection agents.
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 management 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 browser-native HTML5 graphical console for viewing Greenplum Database system metrics and performing certain database administrative tasks. This browser-based application provides the following functionality:
- Interactive overview of realtime system metrics
- Detailed realtime statistics for the cluster and by server
- Query Monitor view lists queries executing and waiting to execute
- Four permission levels to allow users to view or cancel their own or others’ queries, and to view or manage administrative information
- Cluster Metrics view shows synchronized charts of historical system metrics
- History view lists completed queries and system metrics plotted over a selected time period
- Select a query to view query text and explain plan
- Select a query to view query text and explain plan
- Segment Status view with summaries and details by segment
- Storage Status view with summaries and details by segment data directory
- Admin > Permissions view to see or manage permission levels
- Admin > Authentication view to see or edit the
pg_hba.conhost-based authentication configuration file
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 Creating Greenplum Command Center Console Instances.
Greenplum Command Center Web Service
The Greenplum Command Center Console queries the Command Center database through a web service framework composed of a lightweight go-based web server.
The console setup utility,
gpcmdr, sets up the 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.