fix: floor AgentCore Memory event timestamps to milliseconds#573
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Comparing at microsecond precision missed collisions: two events in the same millisecond but different microseconds passed the tie check yet collide once the service floors both to the same millisecond (AgentCore Memory stores and orders eventTimestamp at ms resolution). Floor the desired timestamp to ms first so same-ms events are detected as a tie and separated by 1ms.
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✅ No Breaking Changes DetectedNo public API breaking changes found in this PR. |
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Follow-up to #572 (now merged), addressing @opieter-aws's review feedback.
Problem
_get_monotonic_timestampcompares and stores at microsecond precision (datetime.now()is microsecond-precision), but AgentCore Memory only keeps milliseconds (theeventIdprefix is a ms epoch). So two events in the same millisecond but different microseconds pass the tie check — the later one looks strictly greater — yet collide once the service floors both to the same millisecond. That reintroduces the ambiguous ordering the tie-break is meant to prevent.Change
Floor
desired_timestampto milliseconds before the comparison, so same-ms events are correctly detected as a tie and separated by 1ms.Testing
Two regression tests added to
TestMonotonicTimestamp: timestamps are floored to ms, and a same-millisecond / different-microsecond pair is treated as a tie (second bumped to +1ms). Existingtest_none_desired_uses_current_timeupdated to compare against ms-floored bounds. Memory module green locally (2 unrelated async tests needpytest-asyncio, green in CI).