Common Sub-Expression optimization

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The problem One common pattern we see in some analytical workloads is the repeated use of the same, often times expensive expression. Look at the following query plan for example: The expression JSON_PARSE(features) is used 6 times, and casted to different ROW structures for further processing. Traditionally, Presto would just execute the expression 6 times,…

5 design choices—and 1 weird trick — to get 2x efficiency gains in Presto repartitioning

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We like Presto. We like it a lot — so much we want to make it better in every way. Here’s an example: we just optimized the PartitionedOutputOperator. It’s now 2-3x more CPU efficient, which, when measured against Facebook’s production workload, translates to 6% gains overall. That’s huge. The optimized repartitioning is in use on…