[OpenSTA-users] Performance testing with Open STA

[Osoata, C. <Chr...@at...>]

Hi Michael, Bernie, Danny and Olaf,
=20
>>aim is to identify the number of orders created in an hour by 10
users.
>>Any ideas why I am getting these timeout errors?

< Michael wrote>

> Let's assume you have recorded and modeled your scripts correctly.
>
> Now, you are testing your server performance (throughput) by=20
> identifying the number of orders created in an hour by 10 users,
right?
>
> Aren't you then looking for at what point the load would cause your=20
> server to timing out request?  And bingo, you have reached that point.

Michael,

I understand what you are saying in principle and I don't disagree. When
looking for bottlenecks, a useful technique is to compare throughput vs.

load and see when it becomes non-linear. Frequent timeouts will always
lead to non-linear throughput vs. load (users) graphs.

> Aren't you then looking for at what point the load would cause your=20
> server to timing out request?  And bingo, you have reached that point.

If I understand Chris' email, Chris has found the point where OpenSTA
times out, not the application. I have no idea how long Chris' single
user response times are. If they are just a few seconds, then given the
default 1 minute timeout (actually, the default value is 1 minute but
OpenSTA can take anywhere up to 2X the timeout value to actually deliver
the timeout error to
scripts.) the server(s) have reached a significant bottleneck. If single
user response times started at close to 1 minute, then a response time
of
1.5 minutes would not be that unusual or indicate a bottleneck under
load.


<Chris writes>

Hi there,
Thanks for your response, so does this mean that running the test for 10
users simultaneously should not cause time out errors. The developers
think it may be because it is an unrealistic test i.e. In the real
world, I don't think we will have 10 users running the same test and
performing the same action at the same time for an hour, I think it is
probably best to ramp the test up such that 1 user is added every 30
seconds with a 10 second delay until I get to the maximum number of
users, do you think this is a more realistic test?

Although running the same test now with 10 simultaneous users even
though it displays timeout errors it still creates record in the
database.

Many thanks
Chris




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