Commodore
Commodore
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Does "Simulate a new user on each iteration" flush the dns cache on client side?

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Hello,

 

I have a test scrioted in http/html with 125 Vuser which have an iteration pacing of about 7 sec per iteration. In the runtime settings of PC I have set "Simulate a new user on each iteration" under the browser settings. When this is enabled I noticed that a lot of DNS queries are triggered from the LG's, each time to the same host address and each time it is answered with the proper A record from the DNS server. It seems like this settings also forces a flush of the DNS cache each this a new iteration is started.

 

Is this correct?

 

I am using HP PC 11.52 patch 1

 

Regards,

Peet

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Micro Focus Expert
Micro Focus Expert

What you are seeing is correct behavior, each Vuser acts as a real user, we cannot combine 2 real users activites to 1 action (DNS queries).

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Micro Focus Expert
Micro Focus Expert

I don't think the DNS redirection can be set by VuGen, it should belong to OS or Network setting.

 

Could you change the iteration to 1 and manually run your script few times? Is the DNS request redirected to new host?

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Commodore
Commodore

Sorry maybe my question wasn't fully clear the first time. With the option "Simulate new user on each iteration" I expected that for each iteration the browser would be reset and cookies and cache would be cleared, I did not expect that the client machines DNS cache would be flushed. Here is how I came to thsi conclusion...

With the "Simulate new user on each iteration" option set I performed the following test, with 125 Vusers where each Vuser is running the same script and approaching the same URL:

 

  1. Flushed the DNS cache on the client machine ( = LG) as to force a DNS lookup at the DNS server by the client.
  2. Started wireshark on the client machine with display filter on 'dns'
  3. Started the test

Wireshark now shows very frequent DNS requests all with the same query and the server answers them properly with the correct A record. Apparently for each new Vuser a DNS query is started and also for each iteration a DNS query is started. This last I have verified by tracing again with Wireshark after all Vusers were started: still a lot of DNS request.

Actually I expected a DNS query only once at the very beginning of the test and that it would be stored in the DNS cache. But what I see in the trace is quite different. This leads me to believe that the "Simulate new user on each iteration" setting forces the DNS cache to be flushed at the start of each iteration.

 

But it is something I would like to see confirmed by an HP expert...

 

Regards,

Peet

 

 

 

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Micro Focus Expert
Micro Focus Expert

What you are seeing is correct behavior, each Vuser acts as a real user, we cannot combine 2 real users activites to 1 action (DNS queries).

View solution in original post

Commodore
Commodore

OK, it matches what I see.

Thanks for confirming that.

 

Regards,

Peet

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