Oracle Enqueue Names

为甘州等地区用户提供了全套网页设计制作服务，及甘州网站建设行业解决方案。主营业务为成都网站设计、成都网站建设、甘州网站设计，以传统方式定制建设网站，并提供域名空间备案等一条龙服务，秉承以专业、用心的态度为用户提供真诚的服务。我们深信只要达到每一位用户的要求，就会得到认可，从而选择与我们长期合作。这样，我们也可以走得更远！

Enquences 是为了管理 连续访问数据库资源而设计的一种共享内存结构也叫锁。它们可以与会话或事务相关联。Enquences 名显示在DBA_LOCK和DBA_LOCK_INTERNAL数据字典视图的LOCK_TYPE列中。

资源被唯一地标识一个对象，该对象可以被一个实例(本地资源)或多个实例之间(全局资源)的不同会话锁定。每个想试图锁定资源的会话都在该资源上生成一个队列。

下面是Oracle Enqueues对资源申请的锁模式和申请资源

Enqueues are usually represented in the format "TYPE-ID1-ID2" where:
"TYPE" is a 2 character text string"ID1" is a 4 byte hexadecimal number
"ID2" is a 4 byte hexadecimal number Parameters:
 P1 = Lock Type & Mode
P2 = Lock ID1
P3 = Lock ID2
Lock Type & Mode
The lock type and requested mode are encoded into P1 thus:
Convert P1 into hexadecimal (or use P1RAW) and extract the lock type and requested mode from this by converting the first 2 bytes of the hexadecimal number to ASCII and the second 2 bytes to a number:
Eg: 54580006
    ^^^^------ Converted to ASCII gives "TX" (0x54 = "T", 0x58 = "X")
        ^^^^-- 0006 is 6 in decimal so this is a mode 6 request

Note that on UNIX, the command 'man ascii' will display the Octal, hexadecimal, and decimal ASCII character sets to help with the hex translation.

An alternative way to extract this information is to use SQL thus:
SELECT chr(to_char(bitand(p1,-16777216))/16777215)||
        chr(to_char(bitand(p1, 16711680))/65535) "Lock",
        to_char( bitand(p1, 65535) )    "Mode"
   FROM v$session_wait
  WHERE event = 'enqueue'
;
Lock ID1
 P2 represents ID1 of the enqueue name in decimal.
P2RAW represents ID1 of the enqueue name in hexadecimal.
Lock ID2
 P3 represents ID2 of the enqueue name in decimal.
P3RAW represents ID2 of the enqueue name in hexadecimal.

标题名称：OracleEnqueuesWaitEvents一
标题来源：http://lswzjz.com/article/jdesdd.html