Is ON DUPLICATE KEY UPDATE More Efficient Than Separate Update and Insert in MySQL?

The efficiency of using separate UPDATE and INSERT statements versus using ON DUPLICATE KEY UPDATE in MySQL depends on several factors including the specific use case, the number of rows being affected, and the database schema.

Comparing the Two Approaches

Separate UPDATE and INSERT Flow

- First, you perform an UPDATE to modify existing rows.

- Then, you perform an INSERT for new rows.

Efficiency

- If you have a high number of rows to update and a low number of inserts, this approach might be more efficient because it allows you to optimize each query separately.

- However, it requires two round trips to the database, which can increase overhead, especially if network latency is a concern.

Locking

- Separate queries may lead to more locking and potential contention, especially in a high-concurrency environment.

ON DUPLICATE KEY UPDATE Flow

- You perform a single INSERT statement. If a row with a duplicate key exists, it updates the specified columns.

Efficiency

- This method is generally more efficient for mixed workloads, both updates and inserts, as it combines both operations into one.

- It reduces the number of round trips to the database, which can lead to better performance, especially in high-latency scenarios.

Locking

- It also reduces the locking overhead since only one operation is used, which can be beneficial in concurrent environments.

Considerations