What does "lock | communication buffer resources" mean?

I have an error log which reports a deadlock:

Transaction (Process ID 55) was deadlocked on lock | communication buffer resources with another process and has been chosen as the deadlock victim. Rerun the transaction.

I am trying to reproduce this error, but my standard deadlock SQL code produces a different error:

Transaction (Process ID 54) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.

I want to be very clear that I am not asking what a deadlock is. I do understand the basics.

My question is: what is the meaning of lock | communication buffer resources in this context? What are "communication buffer resources"? Does the lock | signify anything?

My best guess is that a communication buffer is used when parallel threads combine their results. Can anyone confirm or deny this?

My ultimate goal is to somehow trigger the first error to occur again.

Answers


Your issue is parallelism related, and the error has "no meaning" as the error message is not reflecting your problem and no do not go and change the maxdope settings. in order to get to the cause of the error you need to use trace flag 1204 , have a look as to how to use the trace flag and what info you get.

When you do this you'd get the answer as to why, where and what line of code caused the lock. I guess you're able to google your self from that point, and if not then post it and you'll get the answer you need.


You can use MAXDOP 1 as a query hint - i.e. run that query on one cpu - without affecting the rest of the server.

This will avoid the error for that query - doesn't tell you why it's failing but does provide a work-around if you have to get it working fast :-)


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