Oracle 视图 DBA_HIST_BUFFERED_QUEUES 官方解释，作用，如何使用详细说明

本站中文解释

Oracle视图DBA_HIST_BUFFERED_QUEUES存储系统内的缓冲队列的历史状态和性能诊断信息。这些信息可以用来评估系统中的缓冲队列状态，以确定缓冲队列是否扩展或不活跃。主要以下列字段用于检索信息：

• SNAP_ID：DBA_HIST_BUFFERED_QUEUES中抓取历史状态的快照ID。
• SYSTEM_ID：应用程序连接快照所在的系统ID。
• Num_Operations：客户端执行的操作数量。
• Num_Queued：缓冲队列中等待处理的操作数量。
• Reject_Percentage：被拒绝的操作百分比。
• Try_Again_Seconds：客户端在失败后尝试重新连接的时间（以秒为单位）。

使用DBA_HIST_BUFFERED_QUEUES视图可以轻松检索这些信息。例如，可以使用以下查询检索最近的缓冲队列快照：

SELECT *
FROM DBA_HIST_BUFFERED_QUEUES
WHERE SNAP_ID = (SELECT MAX(SNAP_ID)
FROM DBA_HIST_BUFFERED_QUEUES);

官方英文解释

DBA_HIST_BUFFERED_QUEUES displays historical information about all buffered queues available for the instance.

Column	Datatype	NULL	Description
`SNAP_ID`	`NUMBER`	`NOT NULL`	Unique snapshot ID
`DBID`	`NUMBER`	`NOT NULL`	Database ID for the snapshot
`INSTANCE_NUMBER`	`NUMBER`	`NOT NULL`	Instance number for the snapshot
`QUEUE_SCHEMA`	`VARCHAR2(128)`	`NOT NULL`	Owner of the queue
`QUEUE_NAME`	`VARCHAR2(128)`	`NOT NULL`	Name of the queue
`STARTUP_TIME`	`DATE`	`NOT NULL`	Startup time of the instance
`QUEUE_ID`	`NUMBER`	`NOT NULL`	ID of the queue
`NUM_MSGS`	`NUMBER`		Total number of outstanding messages currently enqueued in the buffered queue for the subscriber (includes the count of the messages overflowed to disk)
`SPILL_MSGS`	`NUMBER`		Current number of overflow messages spilled to disk from the buffered queue
`CNUM_MSGS`	`NUMBER`		Cumulative total number of messages enqueued into the buffered queue since the buffered queue was created.
`CSPILL_MSGS`	`NUMBER`		Cumulative total number of overflow messages spilled to disk from the buffered queue since the buffered queue was created
`EXPIRED_MSGS`	`NUMBER`		Number of expired messages
`OLDEST_MSGID`	`RAW(16)`		Message ID of the oldest message
`OLDEST_MSG_ENQTM`	`TIMESTAMP(3)`		Enqueue time of the oldest message
`QUEUE_STATE`	`VARCHAR2(25)`		Indicates whether the queue is in recovery mode (`QUEUE` `IS` `IN` `RECOVERY` `MODE`) or not (`NORMAL`)
`ELAPSED_ENQUEUE_TIME`	`NUMBER`		Total time spent in enqueue (in hundredths of a second)
`ELAPSED_DEQUEUE_TIME`	`NUMBER`		Total time spent in dequeue (in hundredths of a second)
`ELAPSED_TRANSFORMATION_TIME`	`NUMBER`		Total time for evaluating transformations (in hundredths of a second)
`ELAPSED_RULE_EVALUATION_TIME`	`NUMBER`		Total time for rule evaluations (in hundredths of a second)
`ENQUEUE_CPU_TIME`	`NUMBER`		Total CPU time for enqueue (in hundredths of a second)
`DEQUEUE_CPU_TIME`	`NUMBER`		Total CPU time for dequeue (in hundredths of a second)
`LAST_ENQUEUE_TIME`	`TIMESTAMP(3)`		Last message enqueue time
`LAST_DEQUEUE_TIME`	`TIMESTAMP(3)`		Last message dequeue time
`CON_DBID`	`NUMBER`		The database ID of the PDB for the sampled session
`CON_ID`	`NUMBER`		The ID of the container that `CON_DBID` identifies. 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