SPID和KPID的区别

http://support.microsoft.com/kb/117559

"Spid" is the SQL Server process ID number and is assigned by SQL Server to each new connection. It starts with one and is globally unique. It is seen as the spid column of master..sysprocesses, as the spid column from sp_who, or the "Proc ID" column when you select Manage/System in SQL Administrator. 

"Kpid" is the kernel-process ID. Under SQL Server for Windows NT this is the thread ID number, also known as "ID thread," and is assigned by Windows NT when the thread is created. The thread ID number is a system-wide identifier that uniquely identifies the thread and is available by calling the Win32 API GetCurrentThreadID().