Does Caffeine Cache have a default maximum size or memory limit?

[jojaeng2]

Hi, I'm wondering whether Caffeine has a default internal memory limit or maximum size constraint.

Let me first explain the context of why I'm asking this question.

Recently, I noticed what seemed like a memory leak on a server using Caffeine. After some investigation, I realized that the issue was due to not setting any expiration policy on the cache. Since the server was storing cache entries in a linear fashion, stale data kept accumulating, causing a steady increase in memory usage.

I resolved the issue by adding an expiration policy, but what puzzled me was that at some point, memory usage stopped increasing and remained steady, even though I hadn't configured any maximumSize or size-bound eviction in Caffeine.

This behavior made me wonder whether Caffeine has a default maximum size or internal memory limit. However, after checking the documentation and source code, I couldn't find any clear evidence of such a default.

If Caffeine does impose some internal default limit, then this memory behavior would make sense. But if not, I might need to look elsewhere for the cause.

So, my question is:

Does Caffeine have a built-in memory size limit or default maximum size when none is explicitly configured?

If yes, what logic or part of the source code should I look into to understand this behavior?

Any insights would be really helpful. Thanks in advance!

[ben-manes]

Nope, there is no default bounding if you have no policy (maximum, expiration, soft/weak). If you have soft values then the garbage collector is responsible to decide when to evict in low memory situations, but that can cause its own headaches so not typically recommended. I guess something else helped you in this case.

[jojaeng2]

Thank you very much!