Apache Druid

For `index_parallel` this is controlled by split hint: <https://druid.apache.org/docs/latest/ingestion/native-batch/#split-hint-spec>

by default, it's 1 GB per task so you would not get multiple tasks for 400 MB. but you can change it

I personally recommend MSQ, where this is instead controlled by `maxNumTasks` and `taskAssignment`, see <https://druid.apache.org/docs/latest/multi-stage-query/reference#context-parameters>

The logic for how many tasks would be launched is described on that page

Thanks <@U0344FW86DD>! This task was to compare the performance between the index_parallel and MSQE operations. Hence we needed the task to spin up similar number of workers.