Class: SqlQueryAnalyzer::SuggestionEngine

Inherits:
Object
  • Object
show all
Defined in:
lib/sql_query_analyzer/suggestion_engine.rb

Instance Method Summary collapse

Constructor Details

#initialize(explain_output, sql = nil) ⇒ SuggestionEngine

Returns a new instance of SuggestionEngine.



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# File 'lib/sql_query_analyzer/suggestion_engine.rb', line 21

def initialize(explain_output, sql = nil)
  @explain_output = explain_output
  @sql            = sql
end

Instance Method Details

#analyze ⇒ Object 



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# File 'lib/sql_query_analyzer/suggestion_engine.rb', line 26

def analyze
  warnings       = []
  total_cost     = nil
  rows_estimate  = nil
  actual_time    = nil

  # Build the full plan text (all lines) so advisors can see Filters, etc.
  full_plan = @explain_output.map { |row| row["QUERY PLAN"] }.join("\n")

  @explain_output.each_with_index do |row, idx|
    line = row["QUERY PLAN"]

    # Capture cost & estimates
    if line =~ /cost=\d+\.\d+\.\.(\d+\.\d+) rows=(\d+)/
      total_cost    = $1.to_f
      rows_estimate = $2.to_i
    end
    actual_time ||= $1.to_f if line =~ /actual time=(\d+\.\d+)/

    SuggestionRules.all.each do |rule|
      next unless rule[:matcher].call(line)

      suggestion = Suggestion.new(rule[:severity], rule[:message])
      if rule[:message].include?("Sequential Scan")
        dynamic = SequentialScanAdvisor.new(full_plan).enhanced_message
        suggestion = Suggestion.new(rule[:severity], dynamic) if dynamic
      end

      warnings << {
        line_number: idx + 1,
        line_text:   line,
        suggestion:  suggestion
      }
    end
  end

  warnings.concat(SqlLevelRules.evaluate(@sql))

  presenter = QueryPlanPresenter.new(
    output:        @explain_output.map { |r| r["QUERY PLAN"] },
    warnings:      warnings,
    total_cost:    total_cost,
    rows_estimate: rows_estimate,
    actual_time:   actual_time
  )

  presenter.display
  QueryPlanPresenter.classify_cost(total_cost)
end