Blocking Lock History

This application is an SAP tool for gathering data about blocking situations. This function shows blocking situations in the past as opposed to Locks, which shows the current situation. To collect this history, a SQL Server job called SAP CCMS Blocking Lockstats runs once a minute. If blocking lockstats is switched off, this job is disabled.

Display this screen by executing the transaction DBACOCKPIT in the GUI command field and navigating to  Performance  History  Blocking Lock History .

Each line on the ALV display shows a time stamp when a blocking situation occurred, the requesting spid, the blocked spid, the work process pid, the number of open transactions on the blocked spid, and some other self explanatory columns.

The Wait(ms) column is particularly important. It shows how long, in milliseconds, the spid was blocked. The red lines represent the blocked spids. The white lines causing the blocking situation can be deduced by comparing time stamps.

The Wait Resource, Table, and Index columns contain data about the resource involved in the locking conflict. Multiple occurrences of the blocking spid can be shown if the Wait Resource column changes.

The DBCC Input Buffer column displays the command that was executed by the spid, if the required permissions to obtain the data exist.

We recommend analyzing only long running blocking situations in detail. You should place your attention on the scheduling of the custom batch jobs and the blocking these jobs can cause.

Blocking lockstats data that is older than 7 days is deleted once a week during the first run of the job on Sundays.