▚ MODEL AUDIT // 8-bit

// Gemma 4 26B-A4B

FLAWS — Minor Logic Flaws 82/100 tests: PASS

tok/sec58.30

tokens7390

TTFT0.93s

▮ PILLAR BREAKDOWN

Complexity (O(1))

17/20

Concurrency / Races

16/20

Tx Isolation

18/20

Memory & Edges

15/20

Test Integrity

16/20

✓ WENT RIGHT

Tx Isolation (18/20)
Complexity (O(1)) (17/20)
Concurrency / Races (16/20)
Test Integrity (16/20)

✗ WENT WRONG

No pillar fell below 14 — solid across the board.

▮ CRITICAL BUGS

Stale min_freq on manual delete: _remove_node_from_structures empties the min-freq bucket but does `pass` instead of recomputing min_freq (lines 199-202, documented as 'a simplification'). Correct only because eviction has a min_freq-in-freq_map guard + arbitrary-key fallback (lines 237-244) — latent fragility under concurrent deletes.
No __slots__ on Node/DoublyLinkedList/LFUCache/Transaction despite Generic dataclasses (rubric required it for memory efficiency).
Background evictor does list(self.cache_data.keys()) = O(N) snapshot every interval — a linear scan, forbidden by strict O(1).
No MVCC/version check on commit (lost-update possible if the global key changes between tx.get and commit); commit applies deletes->reads->puts without try/except, so a mid-commit exception leaves partial state.

▮ RECOMMENDED USE

Tied top local scorer (82). The only local model to use delta-based transactional frequency accounting (freq bumps deferred to commit), matching the cloud baseline's isolation approach. Reliable for async/ACID-pattern work after a __slots__ + min_freq-edge pass.

▮ REFACTORED PATCH

# FIX 1 (stale min_freq): recompute or invalidate when the min bucket empties.
# In _remove_node_from_structures, replace the `pass`:
if dll.size == 0:
    del self.freq_map[node.freq]
    if self.min_freq == node.freq:
        # bump to next existing tier (frequencies are contiguous under normal use)
        self.min_freq = self.min_freq + 1 if (self.min_freq + 1) in self.freq_map else min(self.freq_map, default=1)

# FIX 2: add __slots__ to Node, DoublyLinkedList, LFUCache, Transaction.
# FIX 3: background evictor — maintain a _ttl_keys set and iterate IT in
# batches instead of list(self.cache_data.keys()) to stay O(batch).
# FIX 4: wrap commit's three loops in try/except with rollback semantics on failure.