Conversion cost and specification on interfaces of key-value stores

•Design an interface description model to abstract interface characteristics.•Quantify and evaluate the difference of two interfaces.•Propose a prototype interfaces as a reference of the interface specification.•Provide guidance for the design of key–value stores' interfaces.

Due to the quick growth of data created and analyzed by industry and business requirements become more complex, many companies come to employ more than one key-value store together to serve different tasks. Considering key-value stores currently define their own interfaces which have different attributes and semantics, interoperability among these key-value stores is weak. To get the best interoperability, we may choose the store whose interfaces are similar to the others, or we may define an interface specification such as SQL specification in relational databases. We propose an interface description model (IDM for short) to abstract interfaces of different key-value stores, and an algorithm to quantify their differences, named as conversion cost. With the help of these algorithms, we can measure and compare the interoperability of given two stores. After studying the interoperability of many stores, we propose an interface prototype, which has the minimum conversion cost to the interfaces of other stores, as a reference to the interface specification of key-value store. Experiments show the features of interfaces, and prove that the proposed prototype has the best interoperability to other typical stores.