When two consecutive compactions each failed to clear the threshold, the
anti-thrashing breaker blocked automatic compaction PERMANENTLY for the
life of the session: nothing decremented _ineffective_compression_count
(or _fallback_compression_streak) while blocked, so a session whose
middle region was briefly too small to compact never auto-compacted
again — it grew unbounded until the provider's hard context limit, and
only /new or /reset recovered it.
Recovery is a probation probe, not amnesty: after
_ANTI_THRASH_RECOVERY_SECONDS (300s) of continuous block the gate grants
exactly ONE attempt by dropping tripped counters to 1 strike (persisted,
so sibling agents on the same session row — gateway hygiene — unblock
too). An ineffective probe re-trips the guard on the next real-usage
verdict and the next recovery waits a full fresh window, so the worst
case in a truly incompressible session is one compaction attempt per
window — bounded, not thrash.
The recovery clock is armed lazily on the first BLOCKED evaluation and
is deliberately not durable: a restart that loads a durable tripped
counter (#69872) starts a full fresh window blocked, preserving the
restart-must-never-disarm contract (#54923).
Fixes#14694
teknium1
62bec4b3f8