Apache Druid - preserving order of elements in a multi-value dimension

I am using Apache Druid to store multi-value dimensions for customers.

While loading data from a CSV, I noticed that the order of the elements in the multi-value dimension is getting changed. E.g. Mumbai|Delhi|Chennai gets ingested as ["Chennai","Mumbai","Delhi"].

It is important for us to preserve the order of elements in order to apply filters in the query using MV_OFFSET function. One work around is to create explicit order element and concatenate it to the element (like ["3~Chennai","1~Mumbai","2~Delhi"])- but this hampers plain group by aggregations.

Is there any way to preserve the order of the elements in a multi-value dimension during load time?

Solution

Thanks to the response from Navis Ryu on Druid slack channel, following dimension spec will keep the order of the elements unchanged:

"dimensions": [
    "page",
    "language",
    { 
        "type": "string",
        "name": "userId", 
        "multiValueHandling": "ARRAY" 
    }
]

More details around the functionality here.