Oracle 视图 V$LATCH_CHILDREN 官方解释，作用，如何使用详细说明

本站中文解释

Oracle视图V$LATCH_CHILDREN是一个动态视图，可以用来查看各类Latch子进程的信息，其中包括执行中的子进程、等待状态的子进程以及正在分配资源的子进程。在系统资源出现负载不均衡时，可以从V$LATCH_CHILDREN视图中把握进程状况。

使用V$LATCH_CHILDREN视图的办法如下：

（1）查看进程的pid

查看当前系统中的所有pid，可以执行：

SELECT sid,pid FROM v$latch_children;

（2）查看进程的执行进度

查看某个进程的执行进度，可以执行：

SELECT sid,pid,percent_complete FROM v$latch_children WHERE pid= pid;

其中 pid指的是进程的pid。

（3）查看进程是否被阻塞

查看某个进程是否被阻塞，可以执行：

SELECT sid,pid,blocking_pid FROM v$latch_children WHERE pid= pid;

其中 pid指的是进程的pid。 若blocking_pid为0，说明该进程没有被阻塞。

官方英文解释

V$LATCH_CHILDREN displays statistics about child latches.

This view includes all columns of V$LATCH plus the CHILD# column. Note that child latches have the same parent if their LATCH# columns match each other.

Number of times the latch was requested in willing-to-wait mode and the requester had to wait

Number of times a willing-to-wait latch request resulted in a session sleeping while waiting for the latch

This column has been deprecated and is present only for compatibility with previous releases of Oracle. No data is accumulated for this column; it will always have a value of zero.

This column has been deprecated and is present only for compatibility with previous releases of Oracle. No data is accumulated for this column; it will always have a value of zero.

Willing-to-wait latch requests which missed the first try but succeeded while spinning

These columns have been deprecated and are present only for compatibility with previous releases of Oracle. No data is accumulated for these columns; they will always have a value of zero. As a substitute for these columns you can query the appropriate rows of the V$EVENT_HISTOGRAM view where the EVENT column has a value of latch free or latch:%.

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.

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数据库远程运维 Oracle 视图 V$LATCH_CHILDREN 官方解释，作用，如何使用详细说明