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From alpinegizmo <...@git.apache.org>
Subject [GitHub] flink pull request #5317: [FLINK-8458] Add the switch for keeping both the o...
Date Mon, 22 Jan 2018 11:10:55 GMT
Github user alpinegizmo commented on a diff in the pull request:

    --- Diff: docs/ops/config.md ---
    @@ -290,6 +290,12 @@ The following parameters configure Flink's JobManager and TaskManagers.
     - `taskmanager.network.numberOfBuffers` (deprecated, replaced by the three parameters
above): The number of buffers available to the network stack. This number determines how many
streaming data exchange channels a TaskManager can have at the same time and how well buffered
the channels are. If a job is rejected or you get a warning that the system has not enough
buffers available, increase this value (DEFAULT: **2048**). If set, it will be mapped to `taskmanager.network.memory.min`
and `taskmanager.network.memory.max` based on `taskmanager.memory.segment-size`.
    +- `taskmanager.network.memory.buffers-per-channel`: Number of network buffers to use
for each outgoing/incoming channel (subpartition/input channel). Especially in credit-based
flow control mode, it indicates how many credits are exclusive in each input channel. It should
be configured at least 2 for good performance. 1 buffer is for receving in-flight data in
the subpartition and 1 buffer is for parallel serialization. 
    --- End diff --
    This needs some clarification. Is taskmanager.network.memory.buffers-per-channel only
used in credit-based flow control mode? Does choosing a value greater than 2 provide any benefit?


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