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99 lines
2.7 KiB
Ruby
99 lines
2.7 KiB
Ruby
# Speeds up #pluck so its about 2.2x faster, importantly makes pluck avoid creation of a slew
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# of AR objects
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#
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require_dependency 'sql_builder'
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class ActiveRecord::Relation
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# Note: In discourse, the following code is included in lib/sql_builder.rb
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#
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# class RailsDateTimeDecoder < PG::SimpleDecoder
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# def decode(string, tuple=nil, field=nil)
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# if Rails.version >= "4.2.0"
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# @caster ||= ActiveRecord::Type::DateTime.new
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# @caster.type_cast_from_database(string)
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# else
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# ActiveRecord::ConnectionAdapters::Column.string_to_time string
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# end
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# end
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# end
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#
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# class ActiveRecordTypeMap < PG::BasicTypeMapForResults
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# def initialize(connection)
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# super(connection)
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# rm_coder 0, 1114
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# add_coder RailsDateTimeDecoder.new(name: "timestamp", oid: 1114, format: 0)
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# # we don't need deprecations
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# self.default_type_map = PG::TypeMapInRuby.new
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# end
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# end
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#
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# def self.pg_type_map
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# conn = ActiveRecord::Base.connection.raw_connection
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# @typemap ||= ActiveRecordTypeMap.new(conn)
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# end
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class ::ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
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def select_raw(arel, name = nil, binds = [], &block)
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arel, binds = binds_from_relation arel, binds
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sql = to_sql(arel, binds)
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execute_and_clear(sql, name, binds, &block)
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end
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end
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def pluck(*cols)
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conn = ActiveRecord::Base.connection
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relation = self
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cols.map! do |column_name|
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if column_name.is_a?(Symbol) && attribute_alias?(column_name)
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attribute_alias(column_name)
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else
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column_name.to_s
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end
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end
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if has_include?(cols.first)
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construct_relation_for_association_calculations.pluck(*cols)
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else
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relation = spawn
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relation.select_values = cols.map { |cn|
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columns_hash.key?(cn) ? arel_table[cn] : cn
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}
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conn.select_raw(relation, nil, relation.bound_attributes) do |result, _|
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result.type_map = SqlBuilder.pg_type_map
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result.nfields == 1 ? result.column_values(0) : result.values
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end
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end
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end
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end
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# require 'benchmark/ips'
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#
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# ENV['RAILS_ENV'] = 'production'
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# require File.expand_path("../../config/environment", __FILE__)
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#
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# Benchmark.ips do |x|
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# x.report("fast_pluck") do
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# Post.where(topic_id: 48464).fast_pluck(:id)
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# end
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#
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# x.report("pluck") do
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# Post.where(topic_id: 48464).pluck(:id)
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# end
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# end
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#
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# % ruby tmp/fast_pluck.rb
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# Calculating -------------------------------------
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# fast_pluck 165.000 i/100ms
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# pluck 80.000 i/100ms
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# -------------------------------------------------
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# fast_pluck 1.720k (± 8.8%) i/s - 8.580k
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# pluck 807.913 (± 4.0%) i/s - 4.080k
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#
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