Module: ValidateFullTableScans

Included in:
PerformanceValidations
Defined in:
lib/performance_promise/validations/full_table_scans.rb

Instance Method Summary collapse

Instance Method Details

#validate_full_table_scans(db_queries, render_time, promised) ⇒ Object 



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# File 'lib/performance_promise/validations/full_table_scans.rb', line 2

def validate_full_table_scans(db_queries, render_time, promised)
  full_table_scans = []
  backtrace = []

  # check the explained queries to see if there were any
  # SCAN TABLEs
  db_queries.each do |db_query|
    if db_query[:explained]
      join_type = db_query[:explained].first[3]
      if join_type

        adapter_name = ActiveRecord::Base.connection.adapter_name
        if adapter_name == 'Mysql2'
          makes_full_table_scan = join_type.match(/ALL/)
          table_name = db_query[:explained][0][2]
        elsif adapter_name == 'SQLite'
          makes_full_table_scan = join_type.match(/SCAN TABLE (.*)/)
          table_name = makes_full_table_scan[1]
        else
          PerformancePromise.configuration.logger.warn("Unkown database adapter {adapter_name}")
          makes_full_table_scan = join_type.match(/SCAN TABLE (.*)/)
          table_name = makes_full_table_scan[1]
        end

        if makes_full_table_scan
          full_table_scans << table_name

          backtrace << db_query[:sql]
          db_query[:trace].each do |trace|
            if trace.starts_with?('app')
              file, line_number = trace.split(':')
              trace = '    |_' +
                File.read(file).split("\n")[line_number.to_i - 1].strip +
                ' (' + trace + ')'
            end
            backtrace << trace
          end

        end
      end
    end
  end

  # we do not care about duplicates
  full_table_scans = full_table_scans.uniq

  # map the models in the promise to their corresponding table names
  promised_full_table_scans = promised.map { |model| model.table_name }

  # check that the performed FTSs are a subset of the promised FTSs
  passes = (full_table_scans & promised_full_table_scans == full_table_scans)
  error_message = ''

  unless passes
      model_names = full_table_scans.map { |table_name| table_name.classify }
      error_message = ":full_table_scans => [#{model_names.join(', ')}]"
  end

  return passes, error_message, backtrace
end