Method: NoBrainer::Criteria::Where::IndexFinder#find_strategy_compound_partial

Defined in:

lib/no_brainer/criteria/where.rb

#find_strategy_compound_partial ⇒ Object

# File 'lib/no_brainer/criteria/where.rb', line 450

def find_strategy_compound_partial
  clauses = get_candidate_clauses(:eq, :between).map { |c| [c.key_path, c] }.to_h
  return nil unless clauses.present?

  get_usable_indexes(:kind => :compound, :geo => false, :multi => false).each do |index|
    indexed_clauses = index.what.map { |field| clauses[[field]] }
    partial_clauses = indexed_clauses.compact
    pad = indexed_clauses.length - partial_clauses.length
    if partial_clauses.any? && partial_clauses.all? { |c| c.try(:compatible_with_index?, index) }
      # can only use partial compound index if:
      #   * index contains all clause fields
      next unless (clauses.values & partial_clauses) == clauses.values
      #   * all clause fields come first in the indexed clauses (unused indexed fields are at the end)
      next unless indexed_clauses.last(pad).all?(&:nil?)
      #   * all clause fields are :eq, except the last (which may be :between)
      next unless partial_clauses[0..-2].all? { |c|  c.op == :eq }

      # use range query to cover unused index fields
      left_bound  = partial_clauses.map(&:value)
      right_bound = partial_clauses.map(&:value)
      if (clause = partial_clauses[-1]).op == :between
        left_bound[-1] = clause.value.min
        right_bound[-1] = clause.value.max
      end
      if pad > 0
        left_bound.append *Array.new(pad, RethinkDB::RQL.new.minval)
        right_bound.append *Array.new(pad, RethinkDB::RQL.new.maxval)
      end
      return IndexStrategy.new(self, ast, partial_clauses, index, :between, [left_bound, right_bound], :left_bound => :closed, :right_bound => :closed)
    end
  end
  nil
end