Eager loading/preloading should be worked regardless of large number of records

Since 213796f, bind params are used for IN clause if enabled prepared
statements.

Unfortunately, most adapter modules have a limitation for # of bind
params (mysql2 65535, pg 65535, sqlite3 250000). So if eager loading
large number of records at once, that query couldn't be sent to the
database.

Since eager loading/preloading queries are auto-generated by Active
Record itself, so it should be worked regardless of large number of
records like as before.

Fixes #33702.
This commit is contained in:
Ryuta Kamizono 2018-09-09 03:30:45 +09:00
parent 82ac7555ab
commit a50eacb03c
6 changed files with 29 additions and 5 deletions

View File

@ -57,10 +57,14 @@ module ActiveRecord
end
def build_bind_attribute(column_name, value)
attr = Relation::QueryAttribute.new(column_name.to_s, value, table.type(column_name))
attr = build_query_attribute(column_name, value)
Arel::Nodes::BindParam.new(attr)
end
def build_query_attribute(column_name, value)
Relation::QueryAttribute.new(column_name.to_s, value, table.type(column_name))
end
protected
def expand_from_hash(attributes)
return ["1=0"] if attributes.empty?

View File

@ -21,10 +21,11 @@ module ActiveRecord
when 0 then NullPredicate
when 1 then predicate_builder.build(attribute, values.first)
else
bind_values = values.map do |v|
predicate_builder.build_bind_attribute(attribute.name, v)
end
attribute.in(bind_values)
values.map! do |v|
attr = predicate_builder.build_query_attribute(attribute.name, v)
attr.value_for_database if attr.boundable?
end.compact!
values.empty? ? NullPredicate : attribute.in(values)
end
unless nils.empty?

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@ -18,6 +18,7 @@ require "models/job"
require "models/subscriber"
require "models/subscription"
require "models/book"
require "models/citation"
require "models/developer"
require "models/computer"
require "models/project"
@ -29,6 +30,18 @@ require "models/sponsor"
require "models/mentor"
require "models/contract"
class EagerLoadingTooManyIdsTest < ActiveRecord::TestCase
fixtures :citations
def test_preloading_too_many_ids
assert_equal Citation.count, Citation.preload(:citations).to_a.size
end
def test_eager_loading_too_may_ids
assert_equal Citation.count, Citation.eager_load(:citations).offset(0).size
end
end
class EagerAssociationTest < ActiveRecord::TestCase
fixtures :posts, :comments, :authors, :essays, :author_addresses, :categories, :categories_posts,
:companies, :accounts, :tags, :taggings, :people, :readers, :categorizations,

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@ -0,0 +1,4 @@
<% 65536.times do |i| %>
fixture_no_<%= i %>:
id: <%= i %>
<% end %>

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@ -2,4 +2,5 @@
class Citation < ActiveRecord::Base
belongs_to :reference_of, class_name: "Book", foreign_key: :book2_id
has_many :citations
end

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@ -160,6 +160,7 @@ ActiveRecord::Schema.define do
create_table :citations, force: true do |t|
t.column :book1_id, :integer
t.column :book2_id, :integer
t.references :citation
end
create_table :clubs, force: true do |t|