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  1. IMPALA
  2. IMPALA-9772

mem_limit docs are stale

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    Details

    • Type: Documentation
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: Docs
    • Labels:
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    • Epic Color:
      ghx-label-13

      Description

      https://impala.apache.org/docs/build/html/topics/impala_mem_limit.html has some discussion about "cancelling queries" that is out of date

      > If query processing exceeds the specified memory limit on any node, either the per-query limit or the impalad limit, Impala cancels the query automatically. Memory limits are checked periodically during query processing, so the actual memory in use might briefly exceed the limit without the query being cancelled.
      This has been out-of-date for a long time. We already have a discussion of what actually happens in the spill-to-disk section here - https://impala.apache.org/docs/build/html/topics/impala_scalability.html. I think all of the information in this paragraph is now inaccurate.

      "Usage notes" should probably refer to the admission control docs, which discusses how to configure memory resource management in detail - https://impala.apache.org/docs/build3x/html/topics/impala_admission.html

      The last bit of the example with the error is also very out of date - that query will either succeed reliably or be rejected by admission control because the memory limit is set too low.

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            • Assignee:
              shajini shajini thayasingh
              Reporter:
              tarmstrong Tim Armstrong
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              • Created:
                Updated: