Class: Benedictus::Heuristics::ExternalSort

Inherits:
Base
  • Object
show all
Defined in:
lib/benedictus/heuristics/external_sort.rb

Instance Method Summary collapse

Methods inherited from Base

apply

Constructor Details

#initialize ⇒ ExternalSort

Returns a new instance of ExternalSort.



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# File 'lib/benedictus/heuristics/external_sort.rb', line 6

def initialize(**)
  super()
end

Instance Method Details

#apply(node) ⇒ Object 



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# File 'lib/benedictus/heuristics/external_sort.rb', line 10

def apply(node)
  return [] unless node.node_type == "Sort"
  return [] unless node.sort_method.to_s.include?("external")

  space = if node.sort_space_used
            " (#{node.sort_space_used} kB on #{node.sort_space_type || "disk"})"
          else
            ""
          end

  [
    warning(
      severity: :critical,
      code: :external_sort,
      message: "Sort spilled to disk via `#{node.sort_method}`#{space}.",
      suggestion: "Increase `work_mem` or add an index that already orders the data."
    )
  ]
end