V$AQ_MESSAGE_CACHE

7.20 V$AQ_MESSAGE_CACHE_ADVICE

V$AQ_MESSAGE_CACHE_ADVICE shows simulated metrics for a range of potential message cache sizes. 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_SUBSHARDS`	`NUMBER`	Estimated number of cached subshards for this size
`ESTD_UNCACHED_SUBSHARDS`	`NUMBER`	Estimated number of uncached subshards for this size
`ESTD_EVICTIONS`	`NUMBER`	Estimated number of subshards evicted for this size
`ESTD_EVICTION_RATE`	`NUMBER`	Estimated number of subshards getting evicted per minute
`ESTD_FG_UNEVICTIONS`	`NUMBER`	Estimated number of subshards unevicted by foreground processes
`ESTD_FG_UNEVICTION_RATE`	`NUMBER`	Estimated number of subshards getting unevicted by foreground processes
`ESTD_BG_UNEVICTIONS`	`NUMBER`	Estimated number of subshards unevicted by background processes
`ESTD_BG_UNEVICTION_RATE`	`NUMBER`	Estimated number of subshards 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_SUBSHARD_SIZE`	`NUMBER`	Simulated average number of messages per cached subshard
`AVG_SUBSHARD_MEMORY`	`NUMBER`	Simulated average memory per cached subshard (in megabytes)
`AVG_EVICTION_TIME`	`NUMBER`	Simulated average time to evict a cached subshard (in milliseconds)
`AVG_UNEVICTION_TIME`	`NUMBER`	Simulated average time to unevict a cached subshard (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