[GitHub] drill pull request #960: DRILL-5815: Option to set query memory as percent o...

[Ben-Zvi <gi...@git.apache.org>]

Github user Ben-Zvi commented on a diff in the pull request:

    https://github.com/apache/drill/pull/960#discussion_r142575862
  
    --- Diff: exec/java-exec/src/main/java/org/apache/drill/exec/util/MemoryAllocationUtilities.java ---
    @@ -56,30 +59,90 @@ public static void setupBufferedOpsMemoryAllocations(final PhysicalPlan plan, fi
         }
     
         // if there are any sorts, compute the maximum allocation, and set it on them
    -    if (bufferedOpList.size() > 0) {
    -      final OptionManager optionManager = queryContext.getOptions();
    -      double cpu_load_average = optionManager.getOption(ExecConstants.CPU_LOAD_AVERAGE);
    -      final long maxWidth = optionManager.getOption(ExecConstants.MAX_WIDTH_PER_NODE);
    -      final long maxWidthPerNode = ExecConstants.MAX_WIDTH_PER_NODE.computeMaxWidth(cpu_load_average,maxWidth);
    -      long maxAllocPerNode = Math.min(DrillConfig.getMaxDirectMemory(),
    -          queryContext.getConfig().getLong(RootAllocatorFactory.TOP_LEVEL_MAX_ALLOC));
    -      maxAllocPerNode = Math.min(maxAllocPerNode,
    -          optionManager.getOption(ExecConstants.MAX_QUERY_MEMORY_PER_NODE_KEY).num_val);
    -      final long maxOperatorAlloc = maxAllocPerNode / (bufferedOpList.size() * maxWidthPerNode);
    -      logger.debug("Max buffered operator alloc: {}", maxOperatorAlloc);
    -
    -      // User configurable option to allow forcing minimum memory.
    -      // Ensure that the buffered ops receive the minimum memory needed to make progress.
    -      // Without this, the math might work out to allocate too little memory.
    -      final long opMinMem = queryContext.getOptions().getOption(ExecConstants.MIN_MEMORY_PER_BUFFERED_OP_KEY).num_val;
    -
    -      for(final PhysicalOperator op : bufferedOpList) {
    -
    -        long alloc = Math.max(maxOperatorAlloc, op.getInitialAllocation());
    -        alloc = Math.max(alloc, opMinMem);
    -        op.setMaxAllocation(alloc);
    -      }
    -    }
         plan.getProperties().hasResourcePlan = true;
    +    if (bufferedOpList.isEmpty()) {
    +      return;
    +    }
    +
    +    // Setup options, etc.
    +
    +    final OptionManager optionManager = queryContext.getOptions();
    +    final long directMemory = DrillConfig.getMaxDirectMemory();
    +
    +    // Compute per-node, per-query memory.
    +
    +    final long maxAllocPerNode = computeQueryMemory(queryContext.getConfig(), optionManager, directMemory);
    +    logger.debug("Memory per query per node: {}", maxAllocPerNode);
    +
    +    // Now divide up the memory by slices and operators.
    +
    +    final long opMinMem = computeOperatorMemory(optionManager, maxAllocPerNode, bufferedOpList.size());
    --- End diff --
    
    An improvement idea: Also include the Hash Join (and the Exchange?) operators in the division math here. Indeed these operators pay no attention to the memory limit, however this would work around the arbitrary fixed %50 assumption; instead dynamically going %100 when there are no Hash Joins, or much smaller when there are many Hash Joins.


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