From 97347d8c409f14b682dd9ec52ded3c869d0ba479 Mon Sep 17 00:00:00 2001 From: Ryuta Kamizono Date: Wed, 13 Mar 2019 09:29:00 +0900 Subject: Support Optimizer Hints We as Arm Treasure Data are using Optimizer Hints with a monkey patch (https://gist.github.com/kamipo/4c8539f0ce4acf85075cf5a6b0d9712e), especially in order to use `MAX_EXECUTION_TIME` (refer #31129). Example: ```ruby class Job < ApplicationRecord default_scope { optimizer_hints("MAX_EXECUTION_TIME(50000) NO_INDEX_MERGE(jobs)") } end ``` Optimizer Hints is supported not only for MySQL but also for most databases (PostgreSQL on RDS, Oracle, SQL Server, etc), it is really helpful to turn heavy queries for large scale applications. --- activerecord/lib/arel/nodes/select_core.rb | 5 +++-- activerecord/lib/arel/nodes/unary.rb | 1 + 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'activerecord/lib/arel/nodes') diff --git a/activerecord/lib/arel/nodes/select_core.rb b/activerecord/lib/arel/nodes/select_core.rb index 73461ff683..5814cae98a 100644 --- a/activerecord/lib/arel/nodes/select_core.rb +++ b/activerecord/lib/arel/nodes/select_core.rb @@ -4,7 +4,7 @@ module Arel # :nodoc: all module Nodes class SelectCore < Arel::Nodes::Node attr_accessor :projections, :wheres, :groups, :windows - attr_accessor :havings, :source, :set_quantifier + attr_accessor :havings, :source, :set_quantifier, :optimizer_hints def initialize super() @@ -42,7 +42,7 @@ module Arel # :nodoc: all def hash [ - @source, @set_quantifier, @projections, + @source, @set_quantifier, @projections, @optimizer_hints, @wheres, @groups, @havings, @windows ].hash end @@ -51,6 +51,7 @@ module Arel # :nodoc: all self.class == other.class && self.source == other.source && self.set_quantifier == other.set_quantifier && + self.optimizer_hints == other.optimizer_hints && self.projections == other.projections && self.wheres == other.wheres && self.groups == other.groups && diff --git a/activerecord/lib/arel/nodes/unary.rb b/activerecord/lib/arel/nodes/unary.rb index 00639304e4..6d1ac36b0e 100644 --- a/activerecord/lib/arel/nodes/unary.rb +++ b/activerecord/lib/arel/nodes/unary.rb @@ -35,6 +35,7 @@ module Arel # :nodoc: all Not Offset On + OptimizerHints Ordering RollUp }.each do |name| -- cgit v1.2.3