Deadlock question

I recently started seeing a new description in the deadlock event. Anyone
have any idea what the underlying issue might be'
"Parallel query worker thread was involved in a deadlock"
Thanks
RichardHi Richard
"Richard Douglass" wrote:

> I recently started seeing a new description in the deadlock event. Anyone
> have any idea what the underlying issue might be'
> "Parallel query worker thread was involved in a deadlock"
> Thanks
> Richard
>
Your query has been chosen to be be run in parallel, check out the topic
"Degree of Parallelism" in books online for more background.
From http://msdn2.microsoft.com/en-us/library/ms178104(SQL.90).aspx
"Coordinator, producer, or consumer threads associated with an exchange port
may block each other causing a deadlock usually when including at least one
other process that is not a part of the parallel query. Also, when a paralle
l
query starts execution, SQL Server determines the degree of parallelism, or
the number of worker threads, based upon the current workload. If the system
workload unexpectedly changes, for example, where new queries start running
on the server or the system runs out of worker threads, then a deadlock coul
d
occur."
If you use the MAXDOP option to specify fewer processors you should not get
this, changing settings such as "cost threshold for parallelism" would affec
t
the whole system so it is probably not a great idea to change that.
John