Was it critical that cache data could be outdated?

Yes, in some cases, data staleness in cache can be critical, especially if the system requires strict consistency and up-to-date information (for example, financial transactions, real-time inventory).n

However, in most cases, a certain degree of data staleness in cache is acceptable to improve performance and reduce load on the database. In such situations, cache invalidation strategies, TTL (time-to-live), or data refresh mechanisms are used.

It is important to assess the requirements for consistency and choose an appropriate balance between access speed and data freshness. If cache data can be outdated, it is necessary to handle such situations, for example, by re-querying the source or notifying the user.