sql-server - sys.dm_os_wait_stats 中的 "MISCELLANEOUS"是什么？

Question

检查sys.dm_os_wait_stats对我来说是这样的:

MISCELLANEOUS 是什么意思？ docs什么也别说。等待统计数据刚刚被清除。 杂项 随着时间的推移稳步增加。

Answer 1

您可能可以忽略它。如果这是您最等待的事情之一，那么您的系统很可能表现得很好(下面的异常(exception))。

来自The SQL Server Wait Type Repository ...

This really should be called "Not Waiting".

This may have been used in SQL 2000 but for 2005/2008, it is not used for any valid wait. It is simply the default wait in a list and isn't used to indicate any real waiting. This type shows up twice in sys.dm_os_wait_stats in SQL 2008 but the "other" instance is an older unused wait type in the code. We should be able to remove it.

另一方面，如果您使用 NEWSEQUENTIALID() 或 CLR，您也可以注意此注释，来自已故 Ken Henderson 的 SQL Server 2005 Waiting and Blocking Issues :

In SQL Server 2005, most of these unusual cases have been converted to more descriptive wait types, but several are still grouped under the MISCELLANEOUS wait type. Of these, two are worth mentioning. The first is synchronization for the NEWSEQUENTIALID built-in function. The other is synchronization of CLR assembly loads. Because these usages get clumped with each other in the MISCELLANEOUS bucket, it is not possible to differentiate between them without examining the statements being executed by the sessions.

这篇文章有点旧，所以 CSS 博客文章可能了解服务包或 2008+ 中发生的更改，而 Ken 在其他时间根本没有配备这些更改(换句话说，这可能是对于您正在运行的 SQL Server 2005 版本来说不一定是这样)。

由于等待类型没有完全记录，所以不太清楚某些等待类型何时以及如何从这个存储桶中升级，但我认为很明显，随着时间的推移，捕获的“有意义的”延迟越来越少在这里。