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Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

In flink Flink batch job, the job is usually divided into multiple parallel tasks executed cross many nodes in the cluster. It is common to encounter the performance degradation on some nodes due to hardware problems or accident I/O busy or high CPU load. This kind of degradation can probably cause the running tasks on the node to be quite slow, that is so called long tail tasks. Although the long tail tasks will not fail, they can severely affect the total job running time. Flink task scheduling does not take this long tail problem into account currently.

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