Question 1

Is Moka cache thread-safe?

Accepted Answer

Yes, Moka's synchronous cache is designed for full concurrency across multiple threads, as shown in the example where multiple threads read and update the cache simultaneously without data races. The asynchronous cache also supports concurrent access in async runtimes.

Question 2

How to implement size-based eviction in Moka?

Accepted Answer

You can use a weigher closure when building the cache to define the weighted size of entries, then set a max capacity. For example, the README shows using string length as weight to limit the cache to 32MiB of values.

Question 3

Moka vs Quick Cache: which one should I choose?

Accepted Answer

Choose Moka if you need advanced features like per-entry expiration, eviction listeners, or lock-free iterators. Quick Cache is better for minimal overhead and smaller dependency trees, as indicated in the feature comparison table. Consider your project's complexity and performance needs.

Question 4

How to use Moka with Tokio for async caching?

Accepted Answer

Enable the 'future' feature in Cargo.toml and use the async cache from the future module. The README provides an example with Tokio, where you await methods like insert and get within async tasks, ensuring proper integration with the async runtime.

Question 5

What expiration policies does Moka support?

Accepted Answer

Moka supports cache-level time-to-live and time-to-idle expiration, as well as per-entry variable expiration. Details and examples are in the expiration policies section, showing how to set durations for automatic entry removal.

Question 6

Can I avoid cloning values when retrieving from Moka?

Accepted Answer

Yes, to avoid expensive clones, wrap values in std::sync::Arc before inserting. The README explains that get returns an owned value, but Arc allows cheap cloning of references, reducing overhead for large data.

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