Add performance warning for MAP_FILTER #25772
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| arguments.stream() | ||
| .skip(1).filter(arg -> { | ||
| String base = arg.getBase(); | ||
| return "function".equals(base) || "lambda".equals(base); |
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"function".equals(base)
Do we have this use case?
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We do have this in some cases
|
|
||
| if (!argumentTypes.isEmpty() && "map".equals(arguments.get(0).getBase())) { | ||
| arguments.stream() | ||
| .skip(1).filter(arg -> { |
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Will this be a problem if there is only one argument?
| String base = arg.getBase(); | ||
| return "function".equals(base) || "lambda".equals(base); | ||
| }).findFirst().ifPresent(arg -> { | ||
| String warningMessage = createWarningMessage(node, "Lambdas on large maps are expensive, consider using map_subset"); |
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Is it possible to also print out the specific function which triggers this warning?
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Description
Add performance warning for MAP_FILTER
Motivation and Context
Partly due to the lack of builtins and partly due to not being familiar, users use lambdas on training tables. We should add a performance warning in the presto analyzer things like MAP_FILTER.
Impact
This will help improve user understanding, as well as prevent issues with performance
Test Plan
Units tests, looking for warnings. Amended tests ensuring new behavior is updated. Removed one obsolete test case
Contributor checklist