Non-relational databases have recently been the preferred
choice when it comes to dealing with Big Data challenges, but their
performance is very sensitive to the chosen data organisations. We
have seen differences of over 70 times in response time for the same
query on different models. This brings users the need to be fully
conscious of the queries they intend to serve in order to design their
data model. The common practice then, is to replicate data into
different models designed to fit different query requirements. In this
scenario, the user is in charge of the code implementation required to
keep consistency between the different data replicas. Manually
replicating data in such high layers of the database results in a lot of
squandered storage due to the underlying system replication
mechanisms that are formerly designed for availability and reliability
ends. We propose and design a mechanism and a prototype to
provide users with transparent management, where queries are
matched with a well-performing model option. Additionally, we
propose to do so by transforming the replication mechanism into a
heterogeneous replication one, in order to avoid squandering disk
space while keeping the availability and reliability features. The
result is a system where, regardless of the query or model the user
specifies, response time will always be that of an affine query.
