Github user NicoK commented on the issue: https://github.com/apache/flink/pull/4529 With the recent update of the netty version in flink-shaded (see https://github.com/apache/flink-shaded/commit/1233f1bb0e2b9fafa4260603aa130b7eb9995a7a), most of this PR is indirectly included. However, I probably need to fall back to the original code creating a copy at least for the fallback non-credit based paths due to the original problem. Additionally, since the introduction of the credit-based flow control we should not use too much memory on the receiver side anymore: memory size in the range of once in our buffers, at most one (or two depending on the above) more copies in netty temporarily. Ultimately, we could go one step further of decoding directly to our buffers here, but that is not covered by this PR and will only work with credit-based flow control.
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