lib/mongo/collection/view/explainable.rb
# frozen_string_literal: true
# rubocop:todo all
# Copyright (C) 2014-2020 MongoDB Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
module Mongo
class Collection
class View
# Defines explain related behavior for collection view.
#
# @since 2.0.0
module Explainable
# The query planner verbosity constant.
#
# @since 2.2.0
QUERY_PLANNER = 'queryPlanner'.freeze
# The execution stats verbosity constant.
#
# @since 2.2.0
EXECUTION_STATS = 'executionStats'.freeze
# The all plans execution verbosity constant.
#
# @since 2.2.0
ALL_PLANS_EXECUTION = 'allPlansExecution'.freeze
# Get the query plan for the query.
#
# @example Get the query plan for the query with execution statistics.
# view.explain(verbosity: :execution_stats)
#
# @option opts [ true | false ] :verbose The level of detail
# to return for MongoDB 2.6 servers.
# @option opts [ String | Symbol ] :verbosity The type of information
# to return for MongoDB 3.0 and newer servers. If the value is a
# symbol, it will be stringified and converted from underscore
# style to camel case style (e.g. :query_planner => "queryPlanner").
#
# @return [ Hash ] A single document with the query plan.
#
# @see https://mongodb.com/docs/manual/reference/method/db.collection.explain/#db.collection.explain
#
# @since 2.0.0
def explain(**opts)
self.class.new(collection, selector, options.merge(explain_options(**opts))).first
end
private
def explained?
!!options[:explain]
end
# @option opts [ true | false ] :verbose The level of detail
# to return for MongoDB 2.6 servers.
# @option opts [ String | Symbol ] :verbosity The type of information
# to return for MongoDB 3.0 and newer servers. If the value is a
# symbol, it will be stringified and converted from underscore
# style to camel case style (e.g. :query_planner => "queryPlanner").
def explain_options(**opts)
explain_limit = limit || 0
# Note: opts will never be nil here.
if Symbol === opts[:verbosity]
opts[:verbosity] = Utils.camelize(opts[:verbosity])
end
{ limit: -explain_limit.abs, explain: opts }
end
end
end
end
end