[jira] [Created] (IMPALA-11690) Estimate codegen memory usage

["Tamas Mate (Jira)" <ji...@apache.org>]

Tamas Mate created IMPALA-11690:
-----------------------------------

             Summary: Estimate codegen memory usage
                 Key: IMPALA-11690
                 URL: https://issues.apache.org/jira/browse/IMPALA-11690
             Project: IMPALA
          Issue Type: Improvement
          Components: Backend, Frontend
    Affects Versions: Impala 4.1.0
            Reporter: Tamas Mate


Codegen memory requirement is estimated only on the backend before allocation:
{code:c++}
  int64_t estimated_memory = ESTIMATED_OPTIMIZER_BYTES_PER_INST
      * counter.GetCount(InstructionCounter::TOTAL_INSTS);
  if (!mem_tracker_->TryConsume(estimated_memory)) {
    const string& msg = Substitute(
        "Codegen failed to reserve '$0' bytes for optimization", estimated_memory);
    return mem_tracker_->MemLimitExceeded(NULL, msg, estimated_memory);
  }
{code}

This can cause problems with dedicated coordinator memory estimates where the memory is more tightly estimated, for example:
{code:none}Query(604397725bdbccbb:8fc7624b00000000): Limit=131.00 MB Reservation=13.94 MB ReservationLimit=99.00 MB OtherMemory=399.55 KB Total=14.33 MB Peak=14.33 MB
  Unclaimed reservations: Reservation=13.94 MB OtherMemory=0 Total=13.94 MB Peak=13.94 MB
...
Dedicated Coordinator Resource Estimate: Memory=131MB
{code}

Impala could apply some heuristics for the codgen memory requirements as well.



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