Switch to AtomicLong for "IngestCurrent" metric to prevent negative values #52581
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Pinging @elastic/es-core-features (:Core/Features/Stats) |
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For monotonically-increasing metrics, the tradeoff of
LongAdder's lower contention for non-atomic value reads tends not to cause problems. The "IngestCurrent" metric is more of a flag-type metric that should hover between zero and a small positive number with frequent increment and decrement operations. In that case,LongAdder's non-atomic reads can result in negative values being returned due to out-of-order application of the increment and decrement operations. Those negative values both confuse users and fail during serialization. For that specific metric,AtomicLong's guarantees are necessary.Fixes #52411, fixes #52406.