Managing system resource usage

You can use the SQL Monitoring APIs (system tables) to track overall resource usage on your cluster.

You can use the Using system tables to track overall resource usage on your cluster. These and the other system tables are described in the Vertica system tables.

If your queries are experiencing errors due to resource unavailability, you can use the following system tables to obtain more details:

System Table Description
RESOURCE_REJECTIONS Monitors requests for resources that are rejected by the Resource manager.
DISK_RESOURCE_REJECTIONS Monitors requests for resources that are rejected due to disk space shortages. See Managing disk space for more information.

When requests for resources of a certain type are being rejected, do one of the following:

  • Increase the resources available on the node by adding more memory, more disk space, and so on. See Managing disk space.

  • Reduce the demand for the resource by reducing the number of users on the system (see Managing sessions), rescheduling operations, and so on.

The LAST_REJECTED_VALUE field in RESOURCE_REJECTIONS indicates the cause of the problem. For example:

  • The message Usage of a single requests exceeds high limit means that the system does not have enough of the resource available for the single request. A common example occurs when the file handle limit is set too low and you are loading a table with a large number of columns.

  • The message Timed out or Canceled waiting for resource reservation usually means that there is too much contention for the resource because the hardware platform cannot support the number of concurrent users using it.