C#, Parallel deserialization of JSON stored in database

A while back ago I had to yield entities constructed by deserializing JSON stored in a database. The first solution just opened a simple single result, sequential reader against the database returning a one column result set containing JSON. This was just yield returned after deserialized to the desired entity. Trying to tweak this I turned to the task parallel library. The idea was to in a separate task, read from the datareade...