dwilliscp (1/16/2013)

---

Is there any SQL that can be added to a Stored Proc to track if there was any blocking of its SQL, or for that matter explain the example below?

I am tasked with explaining, and if possible fixing, jobs that sometimes run more than twice their normal run times. A good example is a program that almost always runs in less than one min, but this morning it took 4 1/2 hours to run. This created problems since our data was not fully loaded when folks started using the application.

Thanks

select * from sys.dm_exec_requests where blocking_session > 0

Suresh B. (1/17/2013)

---

There was no deadlock. Deadlock would fail the job.

dwilliscp (1/17/2013)

---

Thanks I will try and see what I get, but not sure that it will show much if I am just checking for deadlocks. All the job (at that step does) is copy records from one table to update a different table. PerfMon did not show anything abnormal (CPU,Mem,Phy IO), so my guess is that a user was in making changes to the forecast and did not file the screen... but that is just a guess. If I am right it would not have created a deadlock, just blocking.

dwain.c (1/17/2013)

---

Here my experience is a little rough but my understanding is that blocks are a normal process. SQL must block some transactions, allowing others to complete if they've established locks. When a lock is kept and held for too long, the blocked transaction will then be considered in deadlock with it. So that is when SQL Server kicks in to decide which of the transaction processes should be killed.

Lynn Pettis (1/17/2013)

---

A deadlock exists if two processes are are waiting are each waiting for a resource locked by the other process.

tyson.price (1/21/2013)

---

Any old CICS mainframe programmers here remember calling a deadlock a "deadly embrace"? That wasn't limited to just databases, which were relatively new in my environment (we were still using VSAM), but also the resources that you needed to control.