as-cache is an experimental Go library for studying adaptive cache-policy selection. For a general-purpose production cache, start with otter or theine; see the measured comparison.
The best eviction policy depends on the workload. Across twelve published trace workloads, different fixed policies lead. This library measures that choice at runtime: one policy is active and serves requests, while the others run as shadows that track keys and eviction state without payload values. Once per epoch a multi-armed bandit selects a policy. Switching is unconditional by default; optional stability gates can restrict it.
Measurement does not guarantee an improvement or a floor relative to a fixed policy. The current results report repeated observations, small margins and ties, effective sampling, an object/byte comparison and an offline ObserveOnly sweep. ObserveOnly collects advice while keeping the configured policy active. Its final choices are compared retrospectively with standalone policy medians; those differences do not measure a serving loss from following advice.
It is pre-1.0, the API may change, and production use has not been established.
The repository includes nine policy arms; S3-FIFO and SIEVE are experimental
adapters planned for v0.5; their module is excluded from v0.4. The
evidence links to raw results, input checksums and the
measured revision. Reproduce the dataset with the
three-batch recorder; make evidence runs
one diagnostic batch. Random sampling, Random and asynchronous W-TinyLFU mean
some numbers vary between runs. make evidence-check verifies the retained
measurements and exact generated tables without rerunning the experiments.
| Document | Contents |
|---|---|
| Getting started | Install, a working example, and the AdaptiveCache API |
| Design | How it works per request and per epoch, when it fits, the Bandit interface, what is not done |
| Configuration | Every Settings field, migration strategies, sampling, stability gates, tuning |
| Policies | The nine ready-made arms, their caveats, adapting your own cache |
| Advisor mode | ObserveOnly, Advice(), and the metrics module |
| Evidence | Every measured claim: policy tables, competing libraries, real traces, sampling fidelity |
| Benchmarking | Reproducible replays, benchclient, make evidence |
| Releasing | Development workspace, candidate checks, publication and upgrade notes |
| Project site | Project overview and documentation |
Past releases are recorded in the changelog and on the releases page.
Mozilla Public License 2.0 — file-level copyleft. You may use this library in a closed-source application without opening your own code; if you modify one of these files and distribute the result, that file's source must be made available under the same licence. Each publishable module carries its own copy, because a Go module zip contains only its own directory.