What potential difficulties or errors may arise when using data caching in different parts of the system?

When using data caching in different parts of a system, the following difficulties and errors may arise:

• Stale data: cache may contain outdated information if mechanisms for cache updating or invalidation are not implemented.
• Consistency issues: if data changes in the source and the cache is not updated synchronously, this leads to discrepancies.
• Cache overflow: without size limitations, the cache can grow uncontrollably, leading to memory consumption.
• Synchronization difficulties in distributed systems: when multiple application instances are present, cache consistency must be ensured.
• Caching logic errors: incorrect key or caching condition definitions can lead to returning incorrect data.

For example, in Go, when using in-memory cache, it is important to consider that the cache will be lost upon application restart, and a strategy for data clearing and updating should be devised.