What is partitioning and sharding? What is the difference?

Partitioning and sharding are methods of data separation used to improve performance and scalability, but they are applied in different contexts and have distinct differences.

Partitioning is a logical division of data within a single database or table into parts (partitions) based on a specific criterion (for example, by date or value range). Each partition is stored separately, which makes management easier and speeds up queries that work with specific parts of the data.

Sharding is a horizontal division of data across multiple independent servers or nodes (shards). Each shard contains a part of the data, and together they form a complete database. This allows for horizontal scaling of the system by distributing the load.

Main differences:

• Partitioning usually occurs within a single database, sharding is between different databases or servers.
• Partitioning simplifies management and query optimization, sharding scales the system.

Example: in a system with millions of users, partitioning might divide the user table by registration year, while sharding might distribute users across different servers based on their ID hash.