From 0f29c216074c5da6644feddb5184c4881c078b0d Mon Sep 17 00:00:00 2001
From: Sean Griffin <sean@thoughtbot.com>
Date: Fri, 14 Nov 2014 11:20:28 -0700
Subject: Reduce the amount of work performed when instantiating AR models
We don't know which attributes will or won't be used, and we don't want
to create massive bottlenecks at instantiation. Rather than doing *any*
iteration over types and values, we can lazily instantiate the object.
The lazy attribute hash should not fully implement hash, or subclass
hash at any point in the future. It is not meant to be a replacement,
but instead implement its own interface which happens to overlap.
---
.../active_record/attribute_methods/primary_key.rb | 1 +
activerecord/lib/active_record/attribute_set.rb | 14 ++--
.../lib/active_record/attribute_set/builder.rb | 78 +++++++++++++++++-----
activerecord/lib/active_record/core.rb | 2 -
activerecord/lib/active_record/model_schema.rb | 2 +-
5 files changed, 70 insertions(+), 27 deletions(-)
(limited to 'activerecord/lib')
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 9bd333bbac..104d84a1f8 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -120,6 +120,7 @@ module ActiveRecord
def primary_key=(value)
@primary_key = value && value.to_s
@quoted_primary_key = nil
+ @attributes_builder = nil
end
end
end
diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb
index 98ac63c7e1..21c58cbf1d 100644
--- a/activerecord/lib/active_record/attribute_set.rb
+++ b/activerecord/lib/active_record/attribute_set.rb
@@ -2,8 +2,6 @@ require 'active_record/attribute_set/builder'
module ActiveRecord
class AttributeSet # :nodoc:
- delegate :keys, to: :initialized_attributes
-
def initialize(attributes)
@attributes = attributes
end
@@ -25,6 +23,10 @@ module ActiveRecord
attributes.key?(name) && self[name].initialized?
end
+ def keys
+ attributes.initialized_keys
+ end
+
def fetch_value(name, &block)
self[name].value(&block)
end
@@ -43,7 +45,7 @@ module ActiveRecord
end
def initialize_dup(_)
- @attributes = attributes.transform_values(&:dup)
+ @attributes = attributes.dup
super
end
@@ -58,12 +60,6 @@ module ActiveRecord
end
end
- def ensure_initialized(key)
- unless self[key].initialized?
- write_from_database(key, nil)
- end
- end
-
protected
attr_reader :attributes
diff --git a/activerecord/lib/active_record/attribute_set/builder.rb b/activerecord/lib/active_record/attribute_set/builder.rb
index d4a787f2fe..3946e02d10 100644
--- a/activerecord/lib/active_record/attribute_set/builder.rb
+++ b/activerecord/lib/active_record/attribute_set/builder.rb
@@ -1,35 +1,83 @@
module ActiveRecord
class AttributeSet # :nodoc:
class Builder # :nodoc:
- attr_reader :types
+ attr_reader :types, :always_initialized
- def initialize(types)
+ def initialize(types, always_initialized = nil)
@types = types
+ @always_initialized = always_initialized
end
def build_from_database(values = {}, additional_types = {})
- attributes = build_attributes_from_values(values, additional_types)
- add_uninitialized_attributes(attributes)
+ if always_initialized && !values.key?(always_initialized)
+ values[always_initialized] = nil
+ end
+
+ attributes = LazyAttributeHash.new(types, values, additional_types)
AttributeSet.new(attributes)
end
private
+ end
+ end
+
+ class LazyAttributeHash
+ delegate :select, :transform_values, to: :materialize
+ delegate :[], :[]=, :freeze, to: :delegate_hash
+
+ def initialize(types, values, additional_types)
+ @types = types
+ @values = values
+ @additional_types = additional_types
+ @materialized = false
+ @delegate_hash = {}
+ assign_default_proc
+ end
+
+ def key?(key)
+ delegate_hash.key?(key) || values.key?(key) || types.key?(key)
+ end
+
+ def initialized_keys
+ delegate_hash.keys | values.keys
+ end
- def build_attributes_from_values(values, additional_types)
- values.each_with_object({}) do |(name, value), hash|
- type = additional_types.fetch(name, types[name])
- hash[name] = Attribute.from_database(name, value, type)
+ def initialize_dup(_)
+ @delegate_hash = delegate_hash.transform_values(&:dup)
+ assign_default_proc
+ super
+ end
+
+ def initialize_clone(_)
+ @delegate_hash = delegate_hash.clone
+ super
+ end
+
+ protected
+
+ attr_reader :types, :values, :additional_types, :delegate_hash
+
+ private
+
+ def assign_default_proc
+ delegate_hash.default_proc = proc do |hash, name|
+ type = additional_types.fetch(name, types[name])
+
+ if values.key?(name)
+ hash[name] = Attribute.from_database(name, values[name], type)
+ elsif type
+ hash[name] = Attribute.uninitialized(name, type)
end
end
+ end
- def add_uninitialized_attributes(attributes)
- types.each_key do |name|
- next if attributes.key? name
- type = types[name]
- attributes[name] =
- Attribute.uninitialized(name, type)
- end
+ def materialize
+ unless @materialized
+ values.each_key { |key| delegate_hash[key] }
+ types.each_key { |key| delegate_hash[key] }
+ @materialized = true
end
+ delegate_hash
end
end
end
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 952aeaa703..89d8932e9e 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -536,8 +536,6 @@ module ActiveRecord
end
def init_internals
- @attributes.ensure_initialized(self.class.primary_key)
-
@aggregation_cache = {}
@association_cache = {}
@readonly = false
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
index a444aac23c..adad7774b9 100644
--- a/activerecord/lib/active_record/model_schema.rb
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -231,7 +231,7 @@ module ActiveRecord
end
def attributes_builder # :nodoc:
- @attributes_builder ||= AttributeSet::Builder.new(column_types)
+ @attributes_builder ||= AttributeSet::Builder.new(column_types, primary_key)
end
def column_types # :nodoc:
--
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