What Exactly Stale data mean ? How can we Handle this in Cache?

Question

What Exactly Stale data mean ? How can we Handle this in Cache ?

I'm going through Cache and found about stale data. How we can handle it?? How release the stale data if it is not being used? Can someone brief about it ??

Answer 1

Once you store data in a cache, it's like a snapshot of the data. If the data changes, you must flush the cache and reload the data.

Think of it like taking a snapshot of your friends at a sporting event. Once the event is over and your friends leave, the snapshot is 'stale'. It no longer reflects the true status.

Typically, when you know the data has changed, you should flush the cache and let it build back fresh.

Answer 2

Stale Data: The data in cache is outdated with respect to the main memory. How to handle this issue:

1. I understand from the definition that this occurs when the main memory is modified before cache. This is done when the processor accesses the data in main memory directly without accessing it from cache of our consideration.
2. This occurs in the following scenario: When multiple processors are working on same word/data . These processors have different caches and do not share the caches, which causes this issue.
3. The above can be resolved if the processors or cores which are working together have a shared cache.

I too would like some other scenarios where stale data can come into picture.