MyBatis Second-Level Cache: Pros & Cons

The second-level cache in MyBatis refers to caching at the Mapper level to cache query results, reducing the number of database accesses, and improving system performance. Its advantages and disadvantages are as follows:

Advantages:

1. Reduce the number of database accesses to improve system performance: Secondary caching can store query results, allowing for data to be retrieved directly from the cache when the same query request is made, reducing the number of database accesses and enhancing system performance.
2. Improving data consistency: By default, MyBatis’s second-level cache is transactional, ensuring data consistency within the same transaction.
3. Simple Configuration: MyBatis’s second-level cache can be easily enabled or disabled through simple configuration.

Cons:

1. Data not updated in time: The secondary cache is shared under the same SqlSessionFactory, so when one session makes changes to the data, other sessions may not be aware of the changes, leading to delayed data updates.
2. High memory usage: Secondary cache is stored in memory, if the cache data is large, it will occupy a significant amount of memory.
3. The MyBatis second-level cache requires manual refreshing. When data changes, you need to manually clear or refresh the cache.

Overall, MyBatis’s second-level cache can improve system performance, but it also has some drawbacks, so developers need to decide whether to use it based on specific scenarios.