109 lines
4.1 KiB
Ruby
109 lines
4.1 KiB
Ruby
require 'minitest/autorun'
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require 'prism'
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require 'tmpdir'
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# `find_by(id: x)`/`where(id: x).first` go through Relation#rows exactly like
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# any other equality lookup, which used to mean Store#lookup_by_index had to
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# find a registered secondary index covering the 'id' column - but no
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# framework code ever calls `add_index(table, :id)` (id is the primary key,
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# already a Hash key on definition[:rows]), so that search always failed and
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# silently fell back to a full table scan (Store#all). This was real, live
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# behavior, not a theoretical gap: Prism::Authenticatable#current_user calls
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# `authenticatable_model.find_by(id: id)` on every single authenticated
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# request (lib/prism/authenticatable.rb), and examples/blog's
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# ApplicationController#comment_post_label/#comment_post_linkable? call
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# `Post.with_deleted.find_by(id: comment.post_id)` once per rendered comment
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# row - both were full-scanning their table on every hit before this fix
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# (discovered via examples/blog's new AccountController#moderation page,
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# which renders several such rows per response and made the N full scans
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# impossible to miss in the sql.prism log). #lookup_by_index_in already had
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# this exact same "id is always indexed for free" special case for IN-lists
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# (see its own comment) - this closes the matching gap for a plain scalar
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# equality.
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class OrmIdLookupIndexTest < Minitest::Test
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def setup
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@dir = Dir.mktmpdir('prism-id-lookup-index-store')
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@store = CountingIdIndexStore.new(File.join(@dir, 'test.pstore'))
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@store.create_table(:widgets, %w[id sku])
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@a = @store.insert(:widgets, sku: 'AAA')
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@b = @store.insert(:widgets, sku: 'BBB')
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widget_class = Class.new(Prism::Orm::Model) { table_name :widgets }
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widget_class.store = @store
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Object.const_set(:IdLookupWidget, widget_class)
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end
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def teardown
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FileUtils.remove_entry(@dir)
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Object.send(:remove_const, :IdLookupWidget) if Object.const_defined?(:IdLookupWidget)
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end
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def test_lookup_by_index_answers_a_bare_id_equality_without_any_registered_index
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matches = @store.lookup_by_index(:widgets, { 'id' => @a })
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refute_nil matches, 'a plain id equality must never report "no index" (nil means fall back to a full scan)'
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assert_equal ['AAA'], matches.map { |row| row['sku'] }
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end
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def test_lookup_by_index_on_a_missing_id_is_an_empty_hit_not_a_scan_signal
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assert_equal [], @store.lookup_by_index(:widgets, { 'id' => @a + 999 })
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end
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def test_extra_equality_keys_alongside_id_are_still_resolved_by_id_alone
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# No index exists on `sku`, and the wrong sku is paired with the right
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# id - the id lookup still returns the row (Relation#rows re-checks the
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# full condition afterward and would reject it there, not here).
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matches = @store.lookup_by_index(:widgets, { 'id' => @a, 'sku' => 'WRONG' })
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assert_equal ['AAA'], matches.map { |row| row['sku'] }
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end
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def test_model_find_by_id_never_scans
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@store.reset_counts!
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widget = IdLookupWidget.find_by(id: @a)
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assert_equal 'AAA', widget.sku
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assert_equal 0, @store.scan_count
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assert_equal 1, @store.id_index_hits
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end
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def test_where_id_first_never_scans_even_with_an_unrelated_condition_chained_on
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@store.reset_counts!
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widget = IdLookupWidget.where(id: @a).where(sku: 'AAA').first
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assert_equal 'AAA', widget.sku
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assert_equal 0, @store.scan_count
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end
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def test_find_by_id_for_a_nonexistent_row_never_scans
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@store.reset_counts!
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assert_nil IdLookupWidget.find_by(id: @a + 999)
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assert_equal 0, @store.scan_count
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end
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end
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# Same shape as CountingFkIndexStore (test_orm_has_many_foreign_key_index.rb)
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# plus a counter specifically for id-equality hits, since #lookup_by_index is
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# the one method under test here rather than #lookup_by_index_in.
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class CountingIdIndexStore < Prism::Orm::Store
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attr_reader :scan_count, :id_index_hits
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def initialize(*args)
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super
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@scan_count = 0
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@id_index_hits = 0
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end
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def all(table)
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@scan_count += 1
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super
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end
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def lookup_by_index(table, equalities)
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result = super
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@id_index_hits += 1 if !result.nil? && equalities.key?('id')
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result
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end
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def reset_counts!
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@scan_count = 0
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@id_index_hits = 0
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end
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end
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