The Query Monitor view allows you to view information for all Greenplum Database server queries, including details about queries running, queued to run, and blocked by other queries. Users with Admin or Operator permission can see and cancel all users’ queries.
If a Command Center administrator has enabled Query Monitor Guest Access, anyone able to access the Command Center web server can view the system status and query list on this page without signing in to Command Center. Anonymous users, however, cannot cancel queries or access any other Command Center features.
With the information available in this view, Greenplum Database administrators can easily:
- Understand how the system is being used — both in real-time and trending over time.
- Identify and diagnose problem queries while they are running, detect skew, find runaway queries, and so on.
- Review and balance the query load on the system by better optimizing and scheduling the query load.
- Cancel queries that disrupt system performance.
The Query Monitor does not display queries executed by the
gpmon user in the gpperfmon database.
Connecting through an HTTP proxy to the Command Center frontend (client browser), or backend (Command Center agent processes) can prevent the display of any query data in the Query Monitor. See Using an HTTP Proxy Server with Command Center for instructions to disable proxied Command Center connections.
The Query Monitor table displays the following columns for queries.
tmidis a time identifier for the query.
ssidis the session id.
ccntis the number of the command within the session.
- Queued: the query has not yet started to execute
- Running: execution has started, but is not yet complete
- Blocked: the query is waiting for one or more other queries to release locks
- Done: completed successfully
- Cancelling: cancel request sent, cancel pending
- Cancelled: terminated, no longer running
- Idle Transaction: the transaction is open, but idle, for example, waiting while a user in an interactive session enters a statement
Click a column heading to sort the rows on that column in ascending or descending order.
Click the checkbox at the left of a row to choose a query to cancel or export. Click the checkbox in the heading row to choose all queries.
Click Cancel Query to cancel selected queries. A pop-up box prompts you to enter a reason. You can enter a message of up to 128 characters to display with the error message that is received by users whose queries are cancelled.
Click Export to download a comma-separated values (CSV) text file containing rows for the selected queries. When no queries are selected, all rows are exported. The default file name is
Click any query ID to see the Query Details, including metrics, the text of the query, and the query plan.