Introduction to Dispatcher Monitor : DPMON

Diving further into Performance Analysis , So we know that you need all the user request are received by message server and depending on the load it is sent to a Dispatcher has the bandwidth.

How do you define DPMON ?

The DPMON stands for dispatcher monitor, meaning that it can access the main dispatcher monitoring functionalities through OS level. It is similar to SM50 or SM66

In order to use DPMON, you must be logged with the <sid>adm user in the OS level and run the below command.

DPMON is of great use , when because of some reason when we are not able to log in through SAP GUI.

All the request that are received by dispatcher is saved in a dispatcher request queue.

How do you use it ?

dpmon pf=<path to profile / profile name of instance>

[as dispatcher is dependent on instance , every instance has its own dispatcher]

Go to profile directory using:-

cd /usr/sap/<SID>/SYS/profile (or)

cd /sapmnt/<SID>/profile (or)

cdpro

Few Frequently used Different option in dpmon menu :

d or e - You'll have access to the dispatcher queue statistics.

The dispatcher queue statistics are very useful to detect dispatcher queue overflow situations and also bottlenecks in the work processes of an specific instance.

In case you are using the option e in the DPMON main menu, the dispatcher sessions details will also be displayed. This concept was introduced as from kernel 740 and is not present in older releases.

p or l : Work Process admin table : The option p will display the standard view of the work process table and the option l will display the long version of the work process table which includes the columns Action and Action-Info.

You can easily detect system hang situation using l (long version) , where no work process are free to process new requests. This one will clearly display semaphores requested or hold by a work processes. The column state will display the work process status (free, processing or waiting for some action).

[If you understand snapshot and trace file concept then only read further]

The column Action will inform the current action of the work process and Action Info will provide more details about this current action (e.g. Sequential Read in table SWNCMONI).

From this sub menu, option "e - create snapshot" can be used for writing a SERVER SNAPSHOT on the dispatcher trace file.

t : It displays work processes details like number, type, PID, current trace level and components. By using the option t in the menu that will be available inside this functionality you can change the trace level for an specific work process and also specify the components , same as SM50 on GUI.
w : It displays all the communication blocks used by work processes of an specific instance, matching the ID of the block occupied with the PID of the correspondent work process. The work process communication block used by work process for internal server communication.

rdisp/wp_ca_blk_no :The parameter used to mention this count.

m: This functionality can be accessed by using option m in the DPMON main menu. It displays the Message Server status correspondent to the system. The same status displayed in this functionality is also shown in the dispatcher trace dev_disp

These are the basis ones that are used in day to day basis consultant’s life for info about others , Read the mentioned wiki.

What to do when you are not able to login because, no more work process available ?

Use dpmon pf=<profilename>

Will get a display “Dispatcher Queue Statistics” . We can see if any dispatcher waits are there.

press “m” to enter menu

dispatch monitor menu is listed. type “l” view the work process overview.

If all the work processes are full take the PID of the work process having problem and kill using the OS level command Kill -9 <PID>..

After this we can login to the system through SAPGUI.

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