diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md index 3d7508252a08e62e4e377387972afa37ed6ffe6b..148b3800a8f3b41aef99a4a3e77ca498a6052464 100644 --- a/activerecord/CHANGELOG.md +++ b/activerecord/CHANGELOG.md @@ -1,3 +1,28 @@ +* Support Optimizer Hints. + + In most databases, there is a way to control the optimizer is by using optimizer hints, + which can be specified within individual statements. + + Example (for MySQL): + + Topic.optimizer_hints("MAX_EXECUTION_TIME(50000)", "NO_INDEX_MERGE(topics)") + # SELECT /*+ MAX_EXECUTION_TIME(50000) NO_INDEX_MERGE(topics) */ `topics`.* FROM `topics` + + Example (for PostgreSQL with pg_hint_plan): + + Topic.optimizer_hints("SeqScan(topics)", "Parallel(topics 8)") + # SELECT /*+ SeqScan(topics) Parallel(topics 8) */ "topics".* FROM "topics" + + See also: + + * https://dev.mysql.com/doc/refman/8.0/en/optimizer-hints.html + * https://pghintplan.osdn.jp/pg_hint_plan.html + * https://docs.oracle.com/en/database/oracle/oracle-database/12.2/tgsql/influencing-the-optimizer.html + * https://docs.microsoft.com/en-us/sql/t-sql/queries/hints-transact-sql-query?view=sql-server-2017 + * https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.1.0/com.ibm.db2.luw.admin.perf.doc/doc/c0070117.html + + *Ryuta Kamizono* + * Fix query attribute method on user-defined attribute to be aware of typecasted value. For example, the following code no longer return false as casted non-empty string: diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb index 202187a0472075ea1a321bae43ac14d80fd3f7a8..7aad306d502210aef0c415d4b3956712daeb9994 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb @@ -384,6 +384,11 @@ def supports_foreign_tables? false end + # Does this adapter support optimizer hints? + def supports_optimizer_hints? + false + end + def supports_lazy_transactions? false end diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb index a518b897a0605fad207d57df0ee266d317f68cb2..6eefda763fb38dae6ce4d6465905a9db27d3442f 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb @@ -103,6 +103,11 @@ def supports_virtual_columns? mariadb? || version >= "5.7.5" end + # See https://dev.mysql.com/doc/refman/8.0/en/optimizer-hints.html for more details. + def supports_optimizer_hints? + !mariadb? && version >= "5.7.7" + end + def supports_advisory_locks? true end diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb index 672f11cfcb5231ffe945c4185e70cba9c35f6da8..2905660499965b44b0c8ac438bff65b09aecef33 100644 --- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb @@ -351,6 +351,13 @@ def supports_pgcrypto_uuid? postgresql_version >= 90400 end + def supports_optimizer_hints? + unless defined?(@has_pg_hint_plan) + @has_pg_hint_plan = extension_available?("pg_hint_plan") + end + @has_pg_hint_plan + end + def supports_lazy_transactions? true end @@ -381,9 +388,12 @@ def disable_extension(name) } end + def extension_available?(name) + query_value("SELECT true FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA") + end + def extension_enabled?(name) - res = exec_query("SELECT EXISTS(SELECT * FROM pg_available_extensions WHERE name = '#{name}' AND installed_version IS NOT NULL) as enabled", "SCHEMA") - res.cast_values.first + query_value("SELECT installed_version IS NOT NULL FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA") end def extensions diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb index 7a8d0cb663a5c895ab54d720e62ef3eb89904792..86021f0a80a859058e5ee5b2c623183ceb84085e 100644 --- a/activerecord/lib/active_record/querying.rb +++ b/activerecord/lib/active_record/querying.rb @@ -14,7 +14,7 @@ module Querying :find_each, :find_in_batches, :in_batches, :select, :reselect, :order, :reorder, :group, :limit, :offset, :joins, :left_joins, :left_outer_joins, :where, :rewhere, :preload, :eager_load, :includes, :from, :lock, :readonly, :extending, :or, - :having, :create_with, :distinct, :references, :none, :unscope, :merge, :except, :only, + :having, :create_with, :distinct, :references, :none, :unscope, :optimizer_hints, :merge, :except, :only, :count, :average, :minimum, :maximum, :sum, :calculate, :pluck, :pick, :ids ].freeze # :nodoc: diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb index ac37f73b760f45ed9e382aa4705187c478bddb0e..37179774fae4237455304d3d986372fbd8150107 100644 --- a/activerecord/lib/active_record/relation.rb +++ b/activerecord/lib/active_record/relation.rb @@ -5,7 +5,7 @@ module ActiveRecord class Relation MULTI_VALUE_METHODS = [:includes, :eager_load, :preload, :select, :group, :order, :joins, :left_outer_joins, :references, - :extending, :unscope] + :extending, :unscope, :optimizer_hints] SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :reordering, :reverse_order, :distinct, :create_with, :skip_query_cache] diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb index 0f2cff4c9cb770d8f2ddeef2ee6c97b08353c31d..2603fac8b2f6de503b0e35f138841ca10104c2ab 100644 --- a/activerecord/lib/active_record/relation/query_methods.rb +++ b/activerecord/lib/active_record/relation/query_methods.rb @@ -901,6 +901,29 @@ def extending!(*modules, &block) # :nodoc: self end + # Specify optimizer hints to be used in the SELECT statement. + # + # Example (for MySQL): + # + # Topic.optimizer_hints("MAX_EXECUTION_TIME(50000)", "NO_INDEX_MERGE(topics)") + # # SELECT /*+ MAX_EXECUTION_TIME(50000) NO_INDEX_MERGE(topics) */ `topics`.* FROM `topics` + # + # Example (for PostgreSQL with pg_hint_plan): + # + # Topic.optimizer_hints("SeqScan(topics)", "Parallel(topics 8)") + # # SELECT /*+ SeqScan(topics) Parallel(topics 8) */ "topics".* FROM "topics" + def optimizer_hints(*args) + check_if_method_has_arguments!(:optimizer_hints, args) + spawn.optimizer_hints!(*args) + end + + def optimizer_hints!(*args) # :nodoc: + args.flatten! + + self.optimizer_hints_values += args + self + end + # Reverse the existing order clause on the relation. # # User.order('name ASC').reverse_order # generated SQL has 'ORDER BY name DESC' @@ -977,6 +1000,7 @@ def build_arel(aliases) build_select(arel) + arel.optimizer_hints(*optimizer_hints_values) unless optimizer_hints_values.empty? arel.distinct(distinct_value) arel.from(build_from) unless from_clause.empty? arel.lock(lock_value) if lock_value diff --git a/activerecord/lib/arel/nodes/select_core.rb b/activerecord/lib/arel/nodes/select_core.rb index 73461ff683a08c3bcd062250b33ba0da443b5c8b..5814cae98a618f4681b07d1125f1412adc2528c6 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 @@ def initialize_copy(other) def hash [ - @source, @set_quantifier, @projections, + @source, @set_quantifier, @projections, @optimizer_hints, @wheres, @groups, @havings, @windows ].hash end @@ -51,6 +51,7 @@ def eql?(other) 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 00639304e4eb738194dce995de3945026772f717..6d1ac36b0ee9a7a11e135b100b3f75f95d2d8296 100644 --- a/activerecord/lib/arel/nodes/unary.rb +++ b/activerecord/lib/arel/nodes/unary.rb @@ -35,6 +35,7 @@ def eql?(other) Not Offset On + OptimizerHints Ordering RollUp }.each do |name| diff --git a/activerecord/lib/arel/select_manager.rb b/activerecord/lib/arel/select_manager.rb index 0da52ca91bfa556a633e9ca5d04ea24df7e7ff3a..32286b67f461005cb00ab987a4f2f4b559a69bd7 100644 --- a/activerecord/lib/arel/select_manager.rb +++ b/activerecord/lib/arel/select_manager.rb @@ -146,6 +146,13 @@ def projections=(projections) @ctx.projections = projections end + def optimizer_hints(*hints) + unless hints.empty? + @ctx.optimizer_hints = Arel::Nodes::OptimizerHints.new(hints) + end + self + end + def distinct(value = true) if value @ctx.set_quantifier = Arel::Nodes::Distinct.new diff --git a/activerecord/lib/arel/visitors/depth_first.rb b/activerecord/lib/arel/visitors/depth_first.rb index 92d309453c4cf0e73845364ab5d4fdc070771db2..892d670c79886b677873a5b83b6b903f99b1f78b 100644 --- a/activerecord/lib/arel/visitors/depth_first.rb +++ b/activerecord/lib/arel/visitors/depth_first.rb @@ -35,6 +35,7 @@ def unary(o) alias :visit_Arel_Nodes_Ascending :unary alias :visit_Arel_Nodes_Descending :unary alias :visit_Arel_Nodes_UnqualifiedColumn :unary + alias :visit_Arel_Nodes_OptimizerHints :unary def function(o) visit o.expressions diff --git a/activerecord/lib/arel/visitors/dot.rb b/activerecord/lib/arel/visitors/dot.rb index 6389c875cb69d52732684c1d7f8d6e225e11cf0a..ffcbb7a7ab43f853516375b9b56b932526780f33 100644 --- a/activerecord/lib/arel/visitors/dot.rb +++ b/activerecord/lib/arel/visitors/dot.rb @@ -82,6 +82,7 @@ def unary(o) alias :visit_Arel_Nodes_Offset :unary alias :visit_Arel_Nodes_On :unary alias :visit_Arel_Nodes_UnqualifiedColumn :unary + alias :visit_Arel_Nodes_OptimizerHints :unary alias :visit_Arel_Nodes_Preceding :unary alias :visit_Arel_Nodes_Following :unary alias :visit_Arel_Nodes_Rows :unary diff --git a/activerecord/lib/arel/visitors/ibm_db.rb b/activerecord/lib/arel/visitors/ibm_db.rb index 73166054da8c26cc0ccfc7cd2f88fce2a0c228b7..0ffc0725f71a947c7f46e9005175f4441b2d5d45 100644 --- a/activerecord/lib/arel/visitors/ibm_db.rb +++ b/activerecord/lib/arel/visitors/ibm_db.rb @@ -4,6 +4,14 @@ module Arel # :nodoc: all module Visitors class IBM_DB < Arel::Visitors::ToSql private + def visit_Arel_Nodes_SelectCore(o, collector) + collector = super + maybe_visit o.optimizer_hints, collector + end + + def visit_Arel_Nodes_OptimizerHints(o, collector) + collector << "/* #{sanitize_as_sql_comment(o).join} */" + end def visit_Arel_Nodes_Limit(o, collector) collector << "FETCH FIRST " @@ -16,6 +24,10 @@ def is_distinct_from(o, collector) collector = visit [o.left, o.right, 0, 1], collector collector << ")" end + + def collect_optimizer_hints(o, collector) + collector + end end end end diff --git a/activerecord/lib/arel/visitors/informix.rb b/activerecord/lib/arel/visitors/informix.rb index 208fa15aef228841e51c9758aaa7b2514ae2bcfd..cd43be8858ecb3583ac7b8fc048998f9a7d0174d 100644 --- a/activerecord/lib/arel/visitors/informix.rb +++ b/activerecord/lib/arel/visitors/informix.rb @@ -42,10 +42,15 @@ def visit_Arel_Nodes_SelectCore(o, collector) collector end + def visit_Arel_Nodes_OptimizerHints(o, collector) + collector << "/*+ #{sanitize_as_sql_comment(o).join(", ")} */" + end + def visit_Arel_Nodes_Offset(o, collector) collector << "SKIP " visit o.expr, collector end + def visit_Arel_Nodes_Limit(o, collector) collector << "FIRST " visit o.expr, collector diff --git a/activerecord/lib/arel/visitors/mssql.rb b/activerecord/lib/arel/visitors/mssql.rb index fdd864b40dcc328f1cb2e9b8f84cf5a0d45e709d..85815baca222adfdbef8497779344af8554d43f2 100644 --- a/activerecord/lib/arel/visitors/mssql.rb +++ b/activerecord/lib/arel/visitors/mssql.rb @@ -76,6 +76,15 @@ def visit_Arel_Nodes_SelectStatement(o, collector) end end + def visit_Arel_Nodes_SelectCore(o, collector) + collector = super + maybe_visit o.optimizer_hints, collector + end + + def visit_Arel_Nodes_OptimizerHints(o, collector) + collector << "OPTION (#{sanitize_as_sql_comment(o).join(", ")})" + end + def get_offset_limit_clause(o) first_row = o.offset ? o.offset.expr.to_i + 1 : 1 last_row = o.limit ? o.limit.expr.to_i - 1 + first_row : nil @@ -103,6 +112,10 @@ def visit_Arel_Nodes_DeleteStatement(o, collector) end end + def collect_optimizer_hints(o, collector) + collector + end + def determine_order_by(orders, x) if orders.any? orders diff --git a/activerecord/lib/arel/visitors/to_sql.rb b/activerecord/lib/arel/visitors/to_sql.rb index d0dec638602fdecc92c2f7f8f8fe456d0107e2e0..7e3e265208a001c0fc4f8310f46a4f9507d06c45 100644 --- a/activerecord/lib/arel/visitors/to_sql.rb +++ b/activerecord/lib/arel/visitors/to_sql.rb @@ -219,6 +219,7 @@ def visit_Arel_Nodes_SelectOptions(o, collector) def visit_Arel_Nodes_SelectCore(o, collector) collector << "SELECT" + collector = collect_optimizer_hints(o, collector) collector = maybe_visit o.set_quantifier, collector collect_nodes_for o.projections, collector, SPACE @@ -236,6 +237,10 @@ def visit_Arel_Nodes_SelectCore(o, collector) collector end + def visit_Arel_Nodes_OptimizerHints(o, collector) + collector << "/*+ #{sanitize_as_sql_comment(o).join(" ")} */" + end + def collect_nodes_for(nodes, collector, spacer, connector = COMMA) unless nodes.empty? collector << spacer @@ -799,6 +804,14 @@ def quote_column_name(name) @connection.quote_column_name(name) end + def sanitize_as_sql_comment(o) + o.expr.map { |v| v.gsub(%r{ /\*\+?\s* | \s*\*/ }x, "") } + end + + def collect_optimizer_hints(o, collector) + maybe_visit o.optimizer_hints, collector + end + def maybe_visit(thing, collector) return collector unless thing collector << " " diff --git a/activerecord/test/cases/adapters/mysql2/optimizer_hints_test.rb b/activerecord/test/cases/adapters/mysql2/optimizer_hints_test.rb new file mode 100644 index 0000000000000000000000000000000000000000..349de49b36074f9efd9fea0ca4fb60920f38f8d5 --- /dev/null +++ b/activerecord/test/cases/adapters/mysql2/optimizer_hints_test.rb @@ -0,0 +1,24 @@ +# frozen_string_literal: true + +require "cases/helper" +require "models/post" + +if supports_optimizer_hints? + class Mysql2OptimzerHintsTest < ActiveRecord::Mysql2TestCase + fixtures :posts + + def test_optimizer_hints + assert_sql(%r{\ASELECT /\*\+ NO_RANGE_OPTIMIZATION\(posts index_posts_on_author_id\) \*/}) do + posts = Post.optimizer_hints("NO_RANGE_OPTIMIZATION(posts index_posts_on_author_id)") + posts = posts.select(:id).where(author_id: [0, 1]) + assert_includes posts.explain, "| index | index_posts_on_author_id | index_posts_on_author_id |" + end + + assert_sql(%r{\ASELECT /\*\+ NO_RANGE_OPTIMIZATION\(posts index_posts_on_author_id\) \*/}) do + posts = Post.optimizer_hints("/*+ NO_RANGE_OPTIMIZATION(posts index_posts_on_author_id) */") + posts = posts.select(:id).where(author_id: [0, 1]) + assert_includes posts.explain, "| index | index_posts_on_author_id | index_posts_on_author_id |" + end + end + end +end diff --git a/activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb b/activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb new file mode 100644 index 0000000000000000000000000000000000000000..1bfa815cac97bac04224b67bb129d8e0231d5468 --- /dev/null +++ b/activerecord/test/cases/adapters/postgresql/optimizer_hints_test.rb @@ -0,0 +1,28 @@ +# frozen_string_literal: true + +require "cases/helper" +require "models/post" + +if supports_optimizer_hints? + class PostgresqlOptimzerHintsTest < ActiveRecord::PostgreSQLTestCase + fixtures :posts + + def setup + enable_extension!("pg_hint_plan", ActiveRecord::Base.connection) + end + + def test_optimizer_hints + assert_sql(%r{\ASELECT /\*\+ SeqScan\(posts\) \*/}) do + posts = Post.optimizer_hints("SeqScan(posts)") + posts = posts.select(:id).where(author_id: [0, 1]) + assert_includes posts.explain, "Seq Scan on posts" + end + + assert_sql(%r{\ASELECT /\*\+ SeqScan\(posts\) \*/}) do + posts = Post.optimizer_hints("/*+ SeqScan(posts) */") + posts = posts.select(:id).where(author_id: [0, 1]) + assert_includes posts.explain, "Seq Scan on posts" + end + end + end +end diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb index a9ec667ebaf08f651d57f919bee987c993db602d..f95d082907132955d6404836fef8570b3d2dc3d3 100644 --- a/activerecord/test/cases/helper.rb +++ b/activerecord/test/cases/helper.rb @@ -64,6 +64,7 @@ def supports_default_expression? supports_insert_on_duplicate_skip? supports_insert_on_duplicate_update? supports_insert_conflict_target? + supports_optimizer_hints? ].each do |method_name| define_method method_name do ActiveRecord::Base.connection.public_send(method_name) diff --git a/activerecord/test/cases/invertible_migration_test.rb b/activerecord/test/cases/invertible_migration_test.rb index 6cf17ac15db4c8cbc2b32571ab80872faa9dcc81..d68cc401074915c9189b093f71994e84c68d1c99 100644 --- a/activerecord/test/cases/invertible_migration_test.rb +++ b/activerecord/test/cases/invertible_migration_test.rb @@ -308,6 +308,8 @@ def test_migrate_enable_and_disable_extension migration2 = DisableExtension1.new migration3 = DisableExtension2.new + assert_equal true, Horse.connection.extension_available?("hstore") + migration1.migrate(:up) migration2.migrate(:up) assert_equal true, Horse.connection.extension_enabled?("hstore")