V$EQ_MESSAGE_CACHE_ADVICE

V$EQ_MESSAGE_CACHE_ADVICE shows simulated metrics for a range of potential message cache sizes for Transactional Event Queues (TxEventQs). This view assists in cache sizing by providing information in the form of metrics as described below.

Column Datatype Description
SIZE_FOR_ESTIMATE NUMBER Cache size for simulation (in megabytes)
SIZE_FACTOR NUMBER Size factor with respect to the current cache size
ESTD_SIZE_TYPE VARCHAR2(9)

Possible values:

  • MINIMUM: This cache size is required to have all dequeues in-memory (no uncached).

  • CURRENT: This is the current size of the message cache.

  • MAXIMUM: This cache size is required to have zero evictions.

  • NULL: This is the value in all other cases.

ESTD_CACHED_PARTITIONS NUMBER Estimated number of cached event stream partitions for this size
ESTD_UNCACHED_PARTITIONS NUMBER Estimated number of uncached event stream partitions for this size
ESTD_EVICTIONS NUMBER Estimated number of event stream partitions evicted for this size
ESTD_EVICTION_RATE NUMBER Estimated number of event stream partitions getting evicted per minute
ESTD_FG_UNEVICTIONS NUMBER Estimated number of event stream partitions unevicted by foreground processes
ESTD_FG_UNEVICTION_RATE NUMBER Estimated number of event stream partitions getting unevicted by foreground processes
ESTD_BG_UNEVICTIONS NUMBER Estimated number of event stream partitions unevicted by background processes
ESTD_BG_UNEVICTION_RATE NUMBER Estimated number of event stream partitions getting unevicted by background processes
ESTD_BG_PROCESSES NUMBER Estimated number of background processes required for this size
TOTAL_ENQUEUE_RATE NUMBER Simulated number of messages being enqueued per second
TOTAL_DEQUEUE_RATE NUMBER Simulated number of messages being dequeued per second
AVG_PARTITION_SIZE NUMBER Simulated average number of messages per cached event stream partitions
AVG_PARTITION_MEMORY NUMBER Simulated average memory per cached event stream partition (in megabytes)
AVG_EVICTION_TIME NUMBER Simulated average time to evict a cached event stream partition (in milliseconds)
AVG_UNEVICTION_TIME NUMBER Simulated average time to unevict a cached event stream partition (in milliseconds)
FLAGS NUMBER Reserved for internal use
SIMULATION_TIME NUMBER Amount of time that was simulated for (in minutes)
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