What are the main problems that can arise when using caching in ORM systems?

When using caching in ORM (Object-Relational Mapping) systems, the following main issues may arise:

• Data inconsistency (stale data): cache may contain outdated data if changes in the database are not synchronized with the cache.
• Transaction problems: cache may not account for transactional changes, leading to incorrect data states.
• Cache management complexity: the need to properly configure cache lifetime, update, and cleanup strategies.
• Memory and performance: excessive caching can lead to high memory consumption and degraded performance.
• Scaling issues: in distributed systems, synchronizing caches between nodes becomes more complex.

Example: if an application uses a first-level cache (session cache), and an object is modified in another session, the current session may work with outdated data if the cache is not updated.