ORACLE数据库服务热线：13764045638 诗檀软件

摘要： Waits on this event typically occur because an index is missing on the column(s) containing a foreign key constraint. In this case Oracle is forced to acquire a TM lock on the child table during DELET... 阅读全文

摘要： TT 队列锁在官方文档中介绍为TT, Temporary Table，但是实际在版本8i之后该队列锁更多参与在表空间管理事务中。 也可以称enqueue TT为tablespace lock。作用该enqueue TT队列锁用以在各种类型的表空间操作执行过程中避免出现死锁dead lock。 该enqueue lock的 ID2表明正在执行的操作种类，ID1表明该操作对应的表空间号V$Tables... 阅读全文

摘要： SQL> select name from v$event_name where name like '%TX%';NAME----------------------------------------------------------------enq: TX - row lock contentionenq: TX - allocate ITL entryenq: TX - index c... 阅读全文

摘要： This event indicates the session is currently waiting on the Undo Segments and is often related to using system managed undo with an auto tuned undo retention period. In 10g, Oracle added the _undo_au... 阅读全文

摘要： Enqueues are sophisticated locks for managing access to shared resources like tables, rows, jobs, and redo threads. An enqueue can be requested in different levels/mode: null, row share, row exclusive... 阅读全文

摘要： This wait event is experienced whenever the database needs to open a file. Wait time is recorded beginning just prior to when the open request is issued until the time the request is returned, having ... 阅读全文

摘要： ProblemThis will happen if there is no free buffer in the buffer cache for the session to read a new block into. All buffer gets have been suspended.This will frequently occur because DBWR is not writ... 阅读全文

摘要： This wait, also known as global cache buffer busy prior to Oracle 10g, specifies the time the remote instance locally spends accessing the requested data block. This wait event is very similar to the ... 阅读全文

摘要： The session is looking for a consistent read version of data but cannot find it in the local cache. The local instance has made a request to other RAC instances for the data and is waiting on its retu... 阅读全文

摘要： The session is looking for a consistent read version of data but cannot find it in the local cache. The local instance has made a request to other RAC instances for the data and is waiting on its retu... 阅读全文