SAP Web Dispatcher: wdisp/HTTP/ max_pooled_con not working

[Former Member]

Hi Genius,

We have SAP Web Dispatcher in front of our SAP ECC System. The parameter wdisp/HTTP/ max_pooled_con is set to 500 connections. Every HTTP request from the browser passes through Web Dispatcher before hitting ECC. However, this parameter on Web Dispatcher does not seem to be working which results in number of HTTP requests going beyond 500 on ECC. Can anyone please tell what else need to be checked/set/updated/modified to limit the number of HTTP connections to ECC to 500.

Helpful answers will be rewarded.

[Former Member]

Hi Tobias,

Our basis team has setup the parameter wdisp/HTTPS/use_pool_for_new_conn=1 and I can see that under Core System-->Parameters-->Instance Profile. However, still I can notice in SM04 that the number of sessions are going as high as 1200 and even more.

My question is: On WD admin UI, where should this parameter ideally appear, should it be Core System-->Parameters-->Instance Profile OR Dispatching Module -->Parameters?

My requirement is: The number of active connections on Web Dispatcher should not be more than 500 and so my SAP system is not overloaded. However, when I goto Web Admin UI, Core System-->Active Connections, I see many more connections than 500 though all these parameters are set.

Please help...!!!

Thanks,

[Former Member]

Hi,

Want to ask you question as you are checking via sm04 you will have more connection that what is currently passed on from the web dispatcher.

In SM04 you will have all the inactive connection that will get dropped off once the parameter this is reached,

rdisp/plugin_auto_logout

http/security_session_timeout.

Note that the value for the parameter  http/security_session_timeout must deviate from the value for the parameter rdisp/plugin_auto_logout by more than 60 seconds.

My question is: On WD admin UI, where should this parameter ideally appear, should it be Core System-->Parameters-->Instance Profile OR Dispatching Module -->Parameters?

If you want to check the http connection that the web dispatcher connection why done to check

Using the Web Administration Interface (SAP Library - SAP Web Dispatcher)

Thanks

Rishi A brol

[tobias_winterhalter]

Hi Shetul,

These are pretty "internal" parameters that few people should mess with. So they are not exposed by any user interface. If you start Web Dispatcher with trace level 2 or higher, the parameters will be printed into the dev_webdisp trace file during startup.

In case you are using both HTTP and HTTPS connections between Web Dispatcher and back-end, I believe that max_pooled_con needs to be set separately for HTTP and HTTPS:

wdisp/HTTP/max_pooled_con = 500

wdisp/HTTPS/max_pooled_con = 500

On the other hand, the use_pool_for_new_conn parameter only exists as HTTP variant and is then valid for both protocols. So, you would need to set:

wdisp/HTTP/use_pool_for_new_conn = 1

The parameter wdisp/HTTPS/use_pool_for_new_conn has no effect at all!

On second thought, I am not sure if these are the right parameters to achieve your goal. Maybe, you should look into icm/max_conn, either on Web Dispatcher or on back-end side:

http://help.sap.com/saphelp_nw73/helpdata/en/48/3d9f2504bb58d5e10000000a421937/content.htm?frameset=...

And finally, there is the question why there are so many connection at all. Do you really have so many concurrent users? Or is the Keep-alive timeout of the back-end ICM unreasonably high and idle connections are not closed fast enough?

Regards,

Tobias

[Former Member]

Hi Tobias/Everyone,

It was a typo from my side. Our basis team has actually set the parameter wdisp/HTTP/use_pool_for_new_conn=1 being aware of the fact that this single parameter will work both for HTTP and HTTPS.

Also, let me give you more details. As I mentioned earlier, our users access a BSP application that resides on our ECC System over the internet. This BSP application has first page as Login Page which can be accessed by typing a specific URL over the internet. This request flow is as follows:  Client Browser hits F5 Box-->Apache Server-->Web Dispatcher-->SAP System(BSP Application). So, in this scenario, we see around 2000 + http sessions in SM04 when we test the system using automation testing.

Now, our requirement is to eliminate the Apache Server and also limit the number of sessions with SAP system to 500. We want to limit the sessions on Web Dispatcher itself so that not a single request more than 500 hits our SAP System.

Our current configuration(as I can see on WD Admin UI) for some related parameters  is:

1) Core System --> Parameters --> Instance Profile--> Under section 'Configuration for medium scenario'

icm/max_conn = 500

icm/max_sockets = 1024

icm/req_queue_len = 500

icm/min_threads = 10

icm/max_threads = 50

mpi/total_size_MB = 80

wdisp/HTTP/use_pool_for_new_conn=1

2) Under Dispatching module --> Parameters:

wdisp/HTTP/min_pooled_con= 2

wdisp/HTTP/max_pooled_con= 500

wdisp/HTTPS/min_pooled_con= 0

wdisp/HTTPS/max_pooled_con= 500

3) On ECC system(via RZ11):

http/security_session_timeout = 1800 (set by SAP)

rdisp/plugin_auto_logout = 1800(set by SAP)

Note: These two parameters are not set on Web Dispatcher.

Kindly help...

[Former Member]

Hi,

Now, our requirement is to eliminate the Apache Server and also limit the number of sessions with SAP system to 500. We want to limit the sessions on Web Dispatcher itself so that not a single request more than 500 hits our SAP System

as you have a Apache and that would be doing reverse proxy so will have to still have some agent to do reverse proxy in that network if you remove Apache..

Have you check the note for the Cascade web dispatcher.

740234 - Cascade of SAP Web dispatchers

Thanks

Rishi Abrol

.

[tobias_winterhalter]

Hi Shetul,

Sorry, only now I realize that the parameters we discussed so far are all not useful for what you want to achieve. You cannot limit the number of sessions on the Web Dispatcher.

But you can limit the number of users per instance in the backend with parameter rdisp/tm_max_no, and you control how the available slots are distributed per protocol:

icm/<PROT>/context_quota - Administration of the Internet Communication Manager - SAP ...

Regards,

Tobias

[Former Member]

Hi,

I guess you've set the other relevant ones according to the following link:

Overview of Parameters (SAP Library - SAP Web Dispatcher)

There looks like a setting to invoke this limitation, though it does comment that there should be little need to revise it from the default.

Regards,

Graham

[Former Member]

Thanks Graham for the quick response. I did refer this link earlier as well but that parameter does not seem to be working in my case. There is a newer link for 731 as well Overview of Parameters - SAP Web Dispatcher - SAP Library

Let me provide more details of my scenario if that could help someone to guide me properly:

We have a BSP application on ECC which is accessed directly using an URL(no Portal here). This HTTP URL from the Client Browser hits F5 Box-->Apache Server-->Web Dispatcher-->SAP System.

Now, we would like to eliminate this Apache server as it is just being used to throttle the URL with specific sub-string and limit the number of connections to SAP System to 500. We would like to achieve similar functionality only with SAP Web Dispatcher.

I hope this is more clear if someone can help please.

[tobias_winterhalter]

Hi Shetul,

You need to set wdisp/HTTP/use_pool_for_new_conn=1as described here:

Connection Pooling - SAP Web Dispatcher - SAP Library

Regards,

Tobias

[Former Member]

Thanks Tobias... This makes complete sense... I am co-ordinating with basis to get it implemented and test the result. Will get back once done...