Administering Log Files and Work Files

The Command Center components—the backend server, agents, HTTP server, and the gpcc command-line utility—write messages to log files in the $GPCC_HOME/logs directory.

Log files rotate once per day or whenever the component starts or restarts. The current log file is saved to a file with a timestamp in its name and a new log file is started.

The log files can be useful for monitoring and troubleshooting, but you can delete them when you determine they are no longer useful. Remove older log files regularly to conserve disk space.

You can use a utility such as the Linux logrotate utility to manage archived log and data files.

webserver.log

The Command Center backend web server writes to the webserver.log log file on the Command Center host in the $GPCC_HOME/logs directory on the host running Command Center. This is usually the master host, but could also be the standby master host. Messages in this log file describe start-up events, rpc request/response events with agents running on the Greenplum Database segment hosts, and data loading from external tables to the gpmetrics tables in the gpperfmon database.

agent.log

A Command Center agent running on each Greenplum Database host (including the segment and master hosts) logs messages to the agent.log log file in the $GPCC_HOME/logs directory of the host machine. Agents log messages about connections to the Command Center rpc server, periodic data collection events, and metrics transmissions to the rpc port on the backend.

gpccws.log

The Command Center HTTP server writes messages to the gpccws.log file on the Command Center host in the $GPCC_HOME/logs directory. The messages in this log file include server start up messages and Websocket connection events with Command Center clients.

cli.log

The gpcc command-line utility writes messages to the cli.log file in the $GPCC_HOME/logs directory. Whenever the gpcc utility executes, it writes its output to the log file as well as the standard output. The log file is useful for auditing Command Center start and stop events. The cli.log file is not rotated and continues to grow until you archive or delete it manually.

Command Center Work Files

Command Center saves temporary data into files in the $GPCC_HOME/ccdata directory. These files include saved query text files (q*.txt), plan node files (gpccexec*.txt), and table size and statistics information files (gpcc_size_info.dat and gpcc_stat_info.dat). Each night, Command Center archives files in the $GPCC_HOME/ccdata directory that are more than two weeks old. The archive files have names in the format archive_YYYYMMDD_YYYYMMDD.tar.gz, where the dates are the beginning and end dates of the week included in the archive. The archived files are no longer needed by Command Center but may be useful for troubleshooting; you can remove them manually if you do not want to save them.