When parameterizing data, how do I not use the same data more than once in a test?

BIG NEWS! Remember all that messy math we’ve spoken about for months, above? Well, throw it away because a new era has arrived! :smile: :tada:

As of k6 0.34.0 we have released k6/execution which includes a property scenario.iterationInTest. This will return a unique value across all VUs, even in cloud tests!!!

For example:

import exec from "k6/execution";
import { SharedArray } from "k6/data";

const data = new SharedArray("my dataset", function(){
  return JSON.parse(open('my-large-dataset.json'));

export const options = {
  scenarios :{
    "use-all-the-data": {
      executor: "shared-iterations",
      vus: 100,
      iterations: data.length,
      maxDuration: "1h"

export default function() {
  // this is unique even in the cloud
  var item = data[exec.scenario.iterationInTest];
  http.post("https://httpbin.test.k6.io/anything?endpoint=amazing", item)

Full release notes are here: Release v0.34.0 · grafana/k6 · GitHub
Docs on k6/execution: k6/execution