Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/868#discussion_r126825276
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/fragment/SimpleParallelizer.java
---
@@ -72,7 +72,16 @@ public SimpleParallelizer(QueryContext context) {
OptionManager optionManager = context.getOptions();
long sliceTarget =
optionManager.getOption(ExecConstants.SLICE_TARGET).num_val;
this.parallelizationThreshold = sliceTarget > 0 ? sliceTarget : 1;
- this.maxWidthPerNode =
optionManager.getOption(ExecConstants.MAX_WIDTH_PER_NODE_KEY).num_val.intValue();
+ // If the max_width is not set in the validator compute from the cpu
load average
+ long maxWidth =
optionManager.getOption(ExecConstants.MAX_WIDTH_PER_NODE);
+ if(maxWidth == 0) {
+ Double cpu_load_average =
optionManager.getOption(ExecConstants.CPU_LOAD_AVERAGE);
+ this.maxWidthPerNode = (int)
Math.ceil(Runtime.getRuntime().availableProcessors() * cpu_load_average);
--- End diff --
Probably should:
* round result, not take the ceiling
* clamp the number at 1 and the number of processors
```
Math.max(1, Math.min( availProc, Math.round(... * ...) ) )
```
We didn't do this before, but we should have...
This is true if the value was set by a property, so the clamping should be
done regardless of whether the value is retrieved or computed. (Gracefully
handle the case where someone sets the value to 0 or 1 million, say.)
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