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,…

Spatial Joins 1: Local Spatial Joins

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A common type of spatial query involves relating one table of geometric objects (e.g., a table population_centers with columns population, latitude, longitude) with another such table (e.g., a table counties with columns county_name, boundary_wkt), such as calculating for each county the population sum of all population centers contained within it. These kinds of calculations are…