V$EQ_SUBSCRIBER_LOAD

V$EQ_SUBSCRIBER_LOAD describes the load of all subscribers of Transactional Event Queue (TxEventQ) event streams in terms of latency at every instance in an Oracle RAC environment.

Latency denotes the predicted amount of time (in seconds) required from the current time to drain all the messages for that subscriber at each respective instance. The latency calculation considers past enqueue/dequeue rates and future enqueue/dequeue rates based on history.

Column Datatype Description
QUEUE_ID NUMBER Queue ID
QUEUE_SCHEMA VARCHAR2(128) Queue schema
QUEUE_NAME VARCHAR2(128) Queue name
SUBSCRIBER_ID NUMBER Subscriber ID
SUBSCRIBER_NAME VARCHAR2(128) Subscriber name
LATENCY_STATE VARCHAR2(8)

Latency state. Possible values:

  • FINITE - The subscriber will be able to dequeue all the messages in a finite amount of time

  • INFINITE - The subscriber's dequeue rate may not catch up to the enqueue rate

  • UNKNOWN - Latency is not yet known

LATENCY NUMBER Latency (in seconds). Valid only when LATENCY_STATE is FINITE.
DEQUEUE_REQUESTS NUMBER Approximate number of dequeue requests noted recently
ACTIVE_EVENT_STREAM_ID NUMBER Number of event streams that have messages for this subscriber
ACTIVE_LISTENER VARCHAR2(5) Indicates whether the subscriber is actively listening at this instance for messages (TRUE) or not (FALSE)
DEQUEUE_SESSIONS NUMBER Displays the number of active dequeue sessions for this subscriber
FLAGS NUMBER For internal use only
MANDATORY_AFF_SWITCHES NUMBER An affinity switch is a change in the dequeue instance for an event stream-subscriber pair. A mandatory affinity switch is when there are local enqueues in the queue at the instance but no local dequeues present, so the dequeue affinity is switched to another instance for that event stream-subscriber pair. This column shows the number of times mandatory affinity switches were needed from this instance to another for this subscriber.
OPTIONAL_AFF_SWITCHES NUMBER Optional affinity switches are affinity switches that are not mandatory. Optional affinity switches are done for global load balancing across the Oracle Real Application Clusters (Oracle RAC) database. This column shows the number of times optional affinity switches were needed from this instance to another for this subscriber.
CON_ID NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data

See Also: Oracle AI Database Transactional Event Queues and Advanced Queuing User’s Guide for more information about Oracle Transactional Event Queues and Advanced Queuing