Sharding & Partitioning Basics

1. Introduction

This lesson covers the basics of sharding and partitioning in NewSQL databases. These techniques are essential for improving database scalability and performance.

2. Definitions

• Sharding: The process of distributing data across multiple servers, allowing for horizontal scaling.
• Partitioning: The division of a database table into smaller, more manageable pieces called partitions.

3. Sharding

Sharding involves breaking up a database into smaller, more manageable chunks called shards. Each shard is a separate database instance.

3.1 Advantages of Sharding

• Improved performance by distributing load.
• Increased availability through redundancy.
• Elastic scalability to handle growth.

3.2 Example of Sharding

                // Example of a simple sharding strategy
                function getShard(userId) {
                    const shardCount = 4; // Assume we have 4 shards
                    return userId % shardCount; // Simple hash-based sharding
                }
                

4. Partitioning

Partitioning allows a database table to be split into smaller pieces based on certain criteria, improving query performance.

4.1 Types of Partitioning

• Range Partitioning: Partitions are defined based on a range of values.
• List Partitioning: Partitions are defined based on a list of values.
• Hash Partitioning: Uses a hashing function to evenly distribute data.

4.2 Example of Partitioning

                // Example of creating a partitioned table
                CREATE TABLE orders (
                    order_id INT,
                    order_date DATE,
                    amount DECIMAL
                ) PARTITION BY RANGE (YEAR(order_date)) (
                    PARTITION p2021 VALUES LESS THAN (2022),
                    PARTITION p2022 VALUES LESS THAN (2023)
                );
                

5. Best Practices

When implementing sharding and partitioning, consider the following best practices:

• Choose the right shard key to avoid hotspots.
• Monitor performance regularly to adjust shards and partitions.
• Design for failover and redundancy.
• Keep partitions balanced to prevent uneven load distribution.

6. FAQ