Single Table Index vs. Multiple Small Tables: Is Partitioning the Optimal Solution for Large Datasets?

Database Optimization: Evaluate Single Table Indexing vs. Multiple Small Tables without Indexes

In the realm of database optimization, the debate between utilizing a single table with an index or multiple smaller tables without indexes often arises. To shed light on this topic, let's delve into a specific scenario.

Scenario:

Consider a table named 'statistics' with 20,000 users and 30 million rows, featuring columns for user_id, actions, timestamps, etc. Primary query operations involve inserting data based on user_id and retrieving data for specific user_ids.

Question:

Would it be more efficient to leverage an index on a single 'statistics' table or opt for a separate 'statistics' table for each user, eliminating the need for indexes?

Answer:

Using 20,000 tables is not recommended, as it leads to maintenance issues and performance bottlenecks. Instead, MySQL Partitioning provides a solution to optimize performance without sacrificing data integrity.

MySQL Partitioning:

<code class="sql">CREATE TABLE statistics (
  id INT AUTO_INCREMENT NOT NULL,
  user_id INT NOT NULL,
  PRIMARY KEY (id, user_id)
) PARTITION BY HASH(user_id) PARTITIONS 101;</code>

Benefits of Partitioning:

• Faster Data Retrieval: When querying for a specific user_id, MySQL accesses only the relevant partition, significantly reducing the amount of data to be processed.
• Smaller Indexes: Each partition has its own index, resulting in smaller and more manageable indexes.
• Improved Insert Performance: Partitions prevent the index from becoming excessively large, enhancing insert operations.

Considerations:

• Number of Partitions: Use a prime number of partitions (e.g., 101) to evenly distribute data and avoid performance issues associated with a high number of partitions.
• Partition Size: Determine a reasonable partition size based on the projected data volume and performance requirements.
• Data Growth: While HASH partitioning eliminates the need to increase the number of partitions over time, periodic re-partitioning may be necessary to maintain optimal performance.

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