How to make gatling send as many requests as possible?

Question

I have this gatling code (mostly taken from here: https://github.com/gatling-cql/GatlingCql):

val feeder = Iterator.continually(
    Map(
      "id" -> serialGen(),
      "randomString" -> random.nextString(20),
      "randomNum" -> jrandom.nextLong(),
      "randomMap" -> maps(jrandom.nextInt(maps.size))
    ))

  val scn = scenario("Two statements").repeat(1) { 
    feed(feeder)
      .exec(cql("simple SELECT")
        .execute("SELECT * FROM test_table WHERE id = ${randomNum}")
        .consistencyLevel(ConsistencyLevel.LOCAL_QUORUM)
        .check(rowCount.satisfies(a => a >= 0)))
      .exec(cql("prepared INSERT")
        .execute(prepared)
        .withParams("${id}", "${randomMap}", "${randomString}")
        .consistencyLevel(ConsistencyLevel.LOCAL_QUORUM))
  }

  setUp(scn.inject(
    rampUsersPerSec(1) to 1 during (1.minute)
  )).protocols(cqlConfig)

And the repeat(1) thing causes only 2 statements (simple SELECT and prepared INSERT, as defined above) to be executed per user per second. If I do repeat(300) there will be 600 statements per user per second.

What I want is for this code to execute as many as possible statements per second. What modifications do I need to make this this code to achieve that?

Answer 1

Looks like using doWhile instead of repeat achieves this:

 val feeder: Iterator[Map[String, Any]] = Iterator.continually(
    Map(
      "id" -> serialGen(),
      "randomString" -> random.nextString(20),
      "randomNum" -> jrandom.nextLong(),
      "randomMap" -> maps(jrandom.nextInt(maps.size))
    ))

  val scn = scenario("Two statements").doWhile(true) {
    feed(feeder)
      .exec(cql("simple SELECT")
        .execute("SELECT * FROM test_table WHERE id = ${id}")
        .consistencyLevel(ConsistencyLevel.LOCAL_QUORUM)
        .check(rowCount.satisfies(a => a > 0)))
      .exec(cql("prepared INSERT")
        .execute(prepared)
        .withParams("${id}", "${randomMap}", "${randomString}")
        .consistencyLevel(ConsistencyLevel.LOCAL_QUORUM))
  }

  setUp(scn.inject(
    atOnceUsers(10)
  ))
  .protocols(cqlConfig)
  .maxDuration(30.seconds)

  after(session.close())
}