What is the difference between vertical and horizontal partitioning?

Vertical partitioning divides the columns of a table, while horizontal partitioning divides the rows.

Vertical partitioning:

• Division by columns.
• Grouping related columns or separating rarely accessed columns.
• Helps reduce the size of rows read during a query, increasing performance.
• May lead to the need for JOIN operations to retrieve all data of a row.

Horizontal partitioning (sharding):

• Division by rows.
• Data is divided based on a specific criterion (e.g., by ID, date).
• Allows distributing the load across multiple servers/nodes.
• Improves query performance as they process a smaller volume of data on a single node.
• Increases availability and scalability.

Comparison:

Criterion	Vertical partitioning	Horizontal partitioning
What is divided	Columns	Rows
Main goal	Reducing row size, query optimization	Load distribution, scalability
Query complexity	JOINs for full rows	Distributed queries/routing
Data distribution	Within a single server	Between multiple servers/nodes