Application server responce time is high with few users

[Former Member]

Hi experts,

One of my application server is showing high response time with few users and few dialog steps.

Generally concurrent users for this application server is 56 with 1200ms response time for 500 dialog steps.

But some times its showing 9000ms response time with only 9 or 10 users (with 40 dialog steps) for long time.when i checking work process of this application server, all are in waiting status. no job is running. Not only with this application server, all my application servers also behaving like this.

Please give me your suggestions to resolve this.

Regards,

Gayathry.

[Former Member · Accepted solution]

I wonder if this question is already solved?

cheers

[Former Member · Accepted solution]

Hi

Just a thought on the issue, without any further information, it is not possible to give specific hints. But I have seen this behaviour before and one reason could be expensive sql reading lots of rows (blocks/pages).

As soon as lots of users access these data, they will hit buffers very well, and when only a few users are on the system, the data has to be fetched from disk. As soon as buffering is happening the more users accessing the same data, this is always kind of "faster".

On larger systems you can often see longer response times in the morning hours, until the first users cache the data needed.

Regards

Michael

[Former Member · Accepted solution]

In fact it is probably simpler than this but can be a few things.

If you look at the performance in a quiet system the response time is high. That is because it is only Basis transactions running and they normally have long response times. Many users normally means a better response time up to a point. Especially when you include RFC's into the equation as they perform far better as they have no screen processing

A more likely and common on every system type problem is this. One user runs a transaction that takes 20 seconds and you have 5 users in the same 5 minutes that take 1 second. The average response time will be over 4 seconds. But if it was 100 users with a response of 1 second and 1 user with 20 seconds then the response time would be closer to 1 second. 1 single user running a transaction that takes 2 minutes will really screw up your average response time which is why it is a poor performance measurement.

The standard dialog response time is a far better option. An ABAP runs that writes data to an empty table, updates the table and deletes from the table. It then does some ABAP stuff in memory like square roots. If your servers and DB are performing well then your average response time will be a flat line and any spikes indicate performance problems.

Edited by: Graham Newport on Jun 13, 2008 12:36 AM

[Former Member]

Hi!

Are you running instances on a virtual server?

Did you check OS SWAP usage? If you have too much swap utilization you might get this problem...

How many memory server has? Can you please attach ST02 information?

Please note...

https://service.sap.com/sap/support/notes/948066 - Performance Analysis: Transactions to use

Cheers,

Fernando Figueiredo

[Former Member]

Hi Gayathry,

When the response time is too high we need to understand exactly what is happening in the system, you need to start an ST05 trace and need to analyse.

Cheers,

Praveen