Last Vuser not incrementing session var - Custom Data allocation

Gatling (Open-Source)
1

Hello,
I have the following code - attached

I’m trying to allocate X amount of data to each of the users from the csv file (i.e) first 5 values to 1st Vuser and second 5 values to 2nd Vuser and so on
and I’m trying to move the user out of the test, after using those 5 values

When I run it:
the expected result - all the feedCount of each Vuser should get incremented until 6
the actual result - only the final Vuser(in this case 3rd Vuser) is not incrementing the feedCount to 6

if I reduce the Vusers to atOnceUsers(2), the 2nd Vuser is not incrementing the feedCount to 6

I couldnt find where I’m making the mistake, any idea ?

Thanks
Sujin Sam

batchUsers.zip (6.62 KB)

2

Your loop (repeat 6 times) and exit (exit on feedCount > 5) conditions are wrong.
As a result, during last iteration:

  • virtual user 1 is trying to read index 5, which is wrong, it belongs to user 2

  • virtual user 2 is trying to read index 10, which is wrong, it belongs to user 3

  • virtual user 3 is trying to read index 15, which throws because your (0 based) array’s length is 15.

Now, there’s something weird, because you’re supposed to get a stracktrace on such an error. I’m investigating this.

3

I had a doubt that if I add condition inside the session will not work, so added it after the session
I modified the conditions as like below, inside the repeat loop to make it work

exec(session => {
if(session(“feedCount”).as[Int] == allocateCount){
session.markAsFailed
}
else{
session
.set(“p_user”, userRecords(((session.userId).toInt * allocateCount) - allocateCount + session(“feedCount”).as[Int]).get(“p_user”).get)
.set(“feedCount”, (session(“feedCount”).as[Int] + 1))
}
})
.exitHereIfFailed

regarding that un-catched error, will a ticket be created in GitHub?

Thanks
Sujin Sam

4

There’s actually no logging bug in the Gatling.
The issue is with your logback.xml configuration that’s explicitly filtering out not ERROR level.

5

oh, ok got it, Thanks Stephane
I have two doubts here:

  1. if it’s trying to access something that is out of bounds, then the simulation or that Vuser should fail isnt it? is that a good practice?
  2. I haven’t seen this session.markAsFailed in the gatling docs, I learnt this when one of the Dev used it, it is useful. Can this be added to the docs and are there any hidden features like this?