CosmosDB: Is it a good practice to use ORDER BY on the property that is also used in range filter?

Solution 1:

There is no guarantee that a ORDER BY query will use a range index although it normally does.

The best way to ensure you get a good index hit and thus lower RU consumption consistently is to use a composite index like below, of course adjusting your other properties as needed but you can see the _ts part in there as well.

This information can be found in the documentation here

{  
        "automatic":true,
        "indexingMode":"Consistent",
        "includedPaths":[  
            {  
                "path":"/*"
            }
        ],
        "excludedPaths":[],
        "compositeIndexes":[  
            [  
                {  
                    "path":"/foodGroup",
                    "order":"ascending"
        },
                {  
                    "path":"/_ts",
                    "order":"ascending"
                }
            ]
        ]
    }