Metastore is the central repository of Apache Hive metadata. It stores metadata for Hive tables (like their schema and location) and partitions in a relational database. The storage system for the metastore should be optimized for online transactions with random accesses and updates. A file system like HDFS is not suited since it is optimized for sequential scans and not for random access. So, the metastore uses either a traditional relational database (like MySQL, Oracle) or a file system (like local, NFS, AFS) and not HDFS. As a result, HiveQL statements which only access metadata objects are executed with very low latency.