1. A method for compressing objects, comprising: receiving a request to write a first object including a first key and a first value, wherein the first object is of a given type, to an in-memory, non-relational data store; receiving a request to write a second object including a second key and a second value, wherein the second object is of the given type, to the in-memory, non-relational data store; classifying the first object to a compression dictionary according to at least one rule based on a value of the first object and/or the key of the first object; classifying the second object to the compression dictionary according to at least one rule based on a value of the second object and/or the key of the second object; writing the first object to the in-memory, non-relational data store as an uncompressed object before the first object is compressed; compressing the first object and the second object based on the compression dictionary to form a first compressed object and a second compressed object, respectively; and writing the first compressed object and the second compressed object to the in-memory, non-relational data store, wherein writing the first compressed object comprises overwriting the uncompressed object with the first compressed object.