Checking for Failed Segments
With mirroring enabled, you may have failed segments in the system without interruption of service or any indication that a failure has occurred. You can verify the status of your system using the gpstate utility. gpstate provides the status of each individual component of a Greenplum Database system, including primary segments, mirror segments, master, and standby master.
To check for failed segments
- On the master, run the gpstate utility with the
-e option to show segments with error conditions:
$ gpstate -e
Segments in Change Tracking mode indicate the corresponding mirror segment is down. When a segment is not in its preferred role, the segment does not operate in the role to which it was assigned at system initialization. This means the system is in a potentially unbalanced state, as some segment hosts may have more active segments than is optimal for top system performance.
See Recovering From Segment Failures for instructions to fix this situation.
- To get detailed information about a failed segment, check the
gp_segment_configuration catalog table. For
example:
$ psql -c "SELECT * FROM gp_segment_configuration WHERE status='d';"
- For failed segment instances, note the host, port, preferred role, and data directory. This information will help determine the host and segment instances to troubleshoot.
- To show information about mirror segment instances,
run:
$ gpstate -m