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  1. IMPALA
  2. IMPALA-9416

Reduce minimum reservation for shared broadcast join builders

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      This is an optimisation that I'm deferring from IMPALA-9156. The initial version of IMPALA-9156 will be conservative in the amount of memory it reserves for the broadcast join builder.

      We should make it more precise to avoid blowing up the memory requirements. Specifically:

      • the reservation should depend on the number of consuming fragments scheduled, not mt_dop
      • we may want to look at how to reduce the amount of memory reserved per probe side. E.g. use smaller buffer sizes for the probe streams, under the assumption that a broadcast join is unlikely to spill.

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              tarmstrong Tim Armstrong
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