To retrieve n random entities from azure table storage using partition key only.

Question

I have a table named Article which contains 6 different values of partition key and under each partitions key there are 100's of entities, but under each partition key I want to retrieve only n entities back from table. So, I want to query such that it only returns 'n' random entities using partition key only?

Answer 1

I think there is no direct solution. But you can simulate retrieving of random values by specifying random where conditions on CustomKey. CustomKey is technological field, it needed only for solving your problem and has int type. When you adding new item to Azure Table you can assign to this field random value between 0 and 100, for example. Then you can write something like this (based on this article):

var rand = new Random();
var query = from entity in context.CreateQuery<Customer>("CustomersOver30")
            where entity.PartitionKey == "MyPartitionKey" && 
            entity.CustomKey > rand.Next(0, 50) && entity.CustomKey < rand.Next(50, 100)
            select entity;

You will retrive some number of entities, if it will be more or equal your n, just take n items from it. If count of items will be less then n, just repeat this operation untill you will have enought number of items.

Yes, it is hack, but azure tables have very restricted opportunities - only where and top operations are supported.