Microsoft® SQL Server 2012 Unleashed

Identifying Locking Contention

When a client application appears to freeze after submitting a query, this is often due to locking contention. To identify locking contention between processes, you can use the SSMS Activity Monitor, as discussed earlier in this chapter, in the “Monitoring Lock Activity in SQL Server” section; use the sp_who2 stored procedure or query the sys.dm_tran_locks system catalog view. Figure 33.10 shows an example of a blocking lock as viewed in the SSMS Activity Monitor.

FIGURE 33.10 Examining locking contention between two processes in SSMS Activity Monitor.

To identify whether a process is being blocked using sp_who2 ...