Oracle教程 2023-02-25

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

(视图)

Oracle视图DBA_DML_LOCKS提供了对当前的SQL DML锁的信息的丰富表示.它显示系统中正在运行的SELECT、INSERT、UPDATE、DELETE语句中已锁定的对象信息。这个视图只显示获得锁定的语句，不会显示正在wait中的语句。

使用DBA_DML_LOCKS视图可以帮助用户实现基本的性能优化。它可以用来跟踪正在占用锁的DML操作，以帮助检测死锁和系统死循环，并得以正确地处理先前任务被锁住的情况。

DBA_DML_LOCKS lists all DML locks held in the database and all outstanding requests for a DML lock.

Column	Datatype	NULL	Description
`SESSION_ID`	`NUMBER`		Session holding or acquiring the lock
`OWNER`	`VARCHAR2(128)`	`NOT NULL`	Owner of the lock
`NAME`	`VARCHAR2(128)`	`NOT NULL`	Name of the lock
`MODE_HELD`	`VARCHAR2(13)`		The type of lock held. The values are: `ROWS_S` (`SS`): row share lock `ROW-X` (`SX`): row exclusive lock `SHARE` (`S`): share lock `S/ROW-X` (`SSX`): exclusive lock `NONE`: lock requested but not yet obtained
`MODE_REQUESTED`	`VARCHAR2(13)`		Lock request type. The values are: `ROWS_S` (`SS`): row share lock `ROW-X` (`SX`): row exclusive lock `SHARE` (`S`): share lock `S/ROW-X` (`SSX`): exclusive lock `NONE`: Lock identifier obtained; lock not held or requested
`LAST_CONVERT`	`NUMBER`		Time since current mode was granted
`BLOCKING_OTHERS`	`VARCHAR2(40)`		Blocking others