Database system storage technology is mainly composed by Column-Stores (CS) and Row-Stores (RS). Currently, the majority of popular database products use RS, i.e. to store each record's attributes together, such as Microsoft SQL Server, Oracle and so on. Column-Stores database stores data column-by-column. The need for Column-Stores database arose for the efficient query processing in read-intensive relational databases. Also, for read-intensive relational databases, extensive research has performed for efficient data storage and query processing. This paper gives an overview of storage and performance optimization techniques used in Column-Stores.