What Does Database Shard Mean?
A database shard is a horizontal partition in a search engine or database. Each individual partition is known as shard or database shard. Each database shard is kept on a separate database server instance to help in spreading the load. Database shards are based on the fact that after a certain point it is feasible and cheaper to scale sites horizontally than vertically by adding more machines.
Techopedia Explains Database Shard
Within a database, some data always remains in all database shards. In fact, all database shards act as the single source for the unique subset of data. One of the salient features associated with database shards is that they are much faster. Individual database shards can simply outperform a single large database due to its smaller size. There is significant reduction of disk I/O, as the ratio between the memory and data on disk is also improved. This also results in fewer database locks, faster index searches and improvement in individual transaction performances. Database sharding is a highly scalable technique in order to improve the overall performance and throughput of large database-centric business applications and high transactions.
