Oracle 视图 DBA_HIST_LATCH_MISSES_SUMMARY 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_LATCH_MISSES_SUMMARY报告的是系统到目前为止运行的汇总锁等待次数。这些等待次数将用于确定是否存在某种锁定冲突,以及系统可能在特定的锁定保持时间内存在何种瓶颈。不同类型的锁定过程(如读锁、写锁等)也有不同的等待时长,这可以帮助用户更好地分析和诊断因锁而导致的系统性能问题。

使用DBA_HIST_LATCH_MISSES_SUMMARY视图的步骤如下:

1.连接Oracle数据库,登陆到一个特定的用户帐户。

2.使用带有查询条件的SELECT语句查询DBA_HIST_LATCH_MISSES_SUMMARY视图,以获取所需的汇总记录。

3.使用有选择性的GROUP BY语句对DBA_HIST_LATCH_MISSES_SUMMARY视图中的数据进行分组,以获取不同类型的锁定汇总信息。

4.使用带有ORDER BY语句的SELECT语句来根据需要对DBA_HIST_LATCH_MISSES_SUMMARY视图中的结果进行排序和筛选。

5.关闭Oracle数据库。

官方英文解释

DBA_HIST_LATCH_MISSES_SUMMARY displays historical summary statistics about missed attempts to acquire a latch.

This view contains snapshots of V$LATCH_MISSES.

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

PARENT_NAME

VARCHAR2(50)

NOT NULL

Latch name of a parent latch

WHERE_IN_CODE

VARCHAR2(64)

NOT NULL

Location that attempted to acquire the latch

NWFAIL_COUNT

NUMBER

Number of times that no-wait acquisition of the latch failed

SLEEP_COUNT

NUMBER

Number of times that acquisition attempts caused sleeps

WTR_SLP_COUNT

NUMBER

Number of times a waiter slept

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

See Also:

“V$LATCH_MISSES”


数据运维技术 » Oracle 视图 DBA_HIST_LATCH_MISSES_SUMMARY 官方解释,作用,如何使用详细说明