Update Rust crate moka to 0.12.7 - autoclosed

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
moka	dependencies	patch	0.12 -> 0.12.7

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Release Notes

moka-rs/moka (moka)

v0.12.7

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Changed

• Ensure a single call to run_pending_tasks to evict as many entries as possible
  from the cache ([#​417][gh-pull-0417]).

v0.12.6

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Fixed

• Fixed a bug in future::Cache that pending run_pending_tasks calls may cause
  infinite busy loop in an internal schedule_write_op method
  ([#​412][gh-issue-0412]):
  • This bug was introduced in v0.12.0 when the background threads were removed
    from future::Cache.
  • This bug can occur when run_pending_task method is called by user code while
    cache is receiving a very high number of concurrent cache write operations.
    (e.g. insert, get_with, invalidate etc.)
  • When it occurs, the schedule_write_op method will be spinning in a busy loop
    forever, causing high CPU usage and all other async tasks to be starved.

Changed

• Upgraded async-lock crate used by future::Cache from v2.4 to the latest
  v3.3.

v0.12.5

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Added

• Added support for a plain LRU (Least Recently Used) eviction policy
  ([#​390][gh-pull-0390]):
  • The LRU policy is enabled by calling the eviction_policy method of the cache
    builder with a policy obtained by EvictionPolicy::lru function.
  • The default eviction policy remains the TinyLFU (Tiny, Least Frequently Used)
    as it maintains better hit rate than LRU for most use cases. TinyLFU combines
    LRU eviction policy and popularity-based admission policy. A probabilistic data
    structure is used to estimate historical popularity of both hit and missed
    keys. (not only the keys currently in the cache.)
  • However, some use cases may prefer LRU policy over TinyLFU. An example is
    recency biased workload such as streaming data processing. LRU policy can be
    used for them to achieve better hit rate.
  • Note that we are planning to add an adaptive eviction/admission policy called
    Window-TinyLFU in the future. It will adjust the balance between recency and
    frequency based on the current workload.

v0.12.4

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Fixed

• Ensure crossbeam-epoch to run GC when dropping a cache ([#​384][gh-pull-0384]):
  • crossbeam-epoch crate provides an epoch-based memory reclamation scheme for
    concurrent data structures. It is used by Moka cache to safely drop cached
    entries while they are still being accessed by other threads.
  • crossbeam-epoch does its best to reclaim memory (drop the entries evicted
    from the cache) when the epoch is advanced. However, it does not guarantee that
    memory will be reclaimed immediately after the epoch is advanced. This means
    that entries can remain in the memory for a while after the cache is dropped.
  • This fix ensures that, when a cache is dropped, the epoch is advanced and
    crossbeam-epoch's thread local buffers are flushed, helping to reclaim memory
    immediately.
  • Note that there are still chances that some entries remain in the memory for a
    while after a cache is dropped. We are looking for alternatives to
    crossbeam-epoch to improve this situation (e.g. [#​385][gh-issue-0385]).

Added

• Added an example for reinserting expired entries to the cache.
  ([#​382][gh-pull-0382])

v0.12.3

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Added

• Added the upsert and compute methods for modifying a cached entry
  ([#​370][gh-pull-0370]):
  • Now the entry and entry_by_ref APIs have the following methods:
    • and_upsert_with method to insert or update the entry.
    • and_compute_with method to insert, update, remove or do nothing on the
      entry.
    • and_try_compute_with method, which is similar to above but returns
      Result.

Fixed

• Raised the version requirement of the quanta from >=0.11.0, <0.12.0 to
  >=0.12.2, <0.13.0 to avoid under-measuring the elapsed time on Apple silicon
  Macs ([#​376][gh-pull-0376]).
  • Due to this under-measurement, cached entries on macOS arm64 can expire sightly
    later than expected.

v0.12.2

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Fixed

• Prevent timing issues in writes that cause inconsistencies between the cache's
  internal data structures ([#​348][gh-pull-0348]):
  • One way to trigger the issue is that insert the same key twice quickly, once
    when the cache is full and a second time when there is a room in the cache.
    • When it occurs, the cache will not return the value inserted in the second
      call (which is wrong), and the entry_count method will keep returning a non
      zero value after calling the invalidate_all method (which is also wrong).
• Now the last access time of a cached entry is updated immediately after the entry
  is read ([#​363][gh-pull-0363]):
  • When the time-to-idle of a cache is set, the last access time of a cached entry
    is used to determine if the entry has been expired.
  • Before this fix, the access time was updated (to the time when it was read)
    when pending tasks were processed. This delay caused issue that some entries
    become temporarily unavailable for reads even though they have been accessed
    recently. And then they will become available again after the pending tasks are
    processed.
  • Now the last access time is updated immediately after the entry is read. The
    entry will remain valid until the time-to-idle has elapsed.

Note that both of [#​348][gh-pull-0348] and [#​363][gh-pull-0363] were already present
in v0.11.x and older versions. However they were less likely to occur because they
had background threads to periodically process pending tasks. So there were much
shorter time windows for these issues to occur.

Changed

• Updated the Rust edition from 2018 to 2021. ([#​339][gh-pull-0339], by
  [@​nyurik][gh-nyurik])
  • The MSRV remains at Rust 1.65.
• Changed to use inline format arguments throughout the code, including examples.
  ([#​340][gh-pull-0340], by [@​nyurik][gh-nyurik])

Added

• Added an example for cascading drop triggered by eviction ([#​350][gh-pull-0350], by
  [@​peter-scholtens][gh-peter-scholtens])

v0.12.1

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Fixed

• Fixed memory leak in future::Cache that occurred when get_with(),
  entry().or_insert_with(), and similar methods were used ([#​329][gh-issue-0329]).
  • This bug was introduced in v0.12.0. Versions prior to v0.12.0 do not
    have this bug.

Changed

• (Performance) Micro-optimize ValueInitializer ([#​331][gh-pull-0331], by
  [@​Swatinem][gh-Swatinem]).

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