Fix timeouts in source:<url> searches and bookmarklet.

* Change the source index on posts from `(lower(source) gin_trgm_ops) WHERE source != ''`
  to just `(source gin_trgm_ops)`. The WHERE clause prevented the index
  from being used in source:<url> searches because we didn't specify
  the `source != ''` clause in the search itself. Excluding blank
  sources only saved a marginal amount of space anyway. This fixes
  timeouts in source:<url> searches and in the bookmarklet (since we do
  a source dupe check on the upload page too).

* Also switch from indexing `lower(name)` to `name` on pools and users.
  We don't need to lowercase the column because GIN indexes can be used
  with both LIKE and ILIKE queries.

app/logical/post_query_builder.rb

@@ -197,7 +197,7 @@ class PostQueryBuilder
 
     if q[:source]
       if q[:source] == "none"
-        relation = relation.where("posts.source = ''")
+        relation = relation.where_like(:source, '')
       else
         relation = relation.where_ilike(:source, q[:source].downcase + "*")
       end
@@ -205,7 +205,7 @@ class PostQueryBuilder
 
     if q[:source_neg]
       if q[:source_neg] == "none"
-        relation = relation.where("posts.source != ''")
+        relation = relation.where_not_like(:source, '')
       else
         relation = relation.where_not_ilike(:source, q[:source_neg].downcase + "*")
       end

app/models/application_record.rb

@@ -18,11 +18,11 @@ class ApplicationRecord < ActiveRecord::Base
       end
 
       def where_ilike(attr, value)
-        where("lower(#{qualified_column_for(attr)}) LIKE ? ESCAPE E'\\\\'", value.mb_chars.downcase.to_escaped_for_sql_like)
+        where("#{qualified_column_for(attr)} ILIKE ? ESCAPE E'\\\\'", value.mb_chars.to_escaped_for_sql_like)
       end
 
       def where_not_ilike(attr, value)
-        where.not("lower(#{qualified_column_for(attr)}) LIKE ? ESCAPE E'\\\\'", value.mb_chars.downcase.to_escaped_for_sql_like)
+        where.not("#{qualified_column_for(attr)} ILIKE ? ESCAPE E'\\\\'", value.mb_chars.to_escaped_for_sql_like)
       end
 
       # https://www.postgresql.org/docs/current/static/functions-matching.html#FUNCTIONS-POSIX-REGEXP

app/models/pool.rb

@@ -47,7 +47,7 @@ class Pool < ApplicationRecord
     def name_matches(name)
       name = normalize_name_for_search(name)
       name = "*#{name}*" unless name =~ /\*/
-      where("lower(pools.name) like ? escape E'\\\\'", name.to_escaped_for_sql_like)
+      where_ilike(:name, name)
     end
 
     def default_order
@@ -108,7 +108,7 @@ class Pool < ApplicationRecord
     if name =~ /^\d+$/
       where("pools.id = ?", name.to_i).first
     elsif name
-      where("lower(pools.name) = ?", normalize_name_for_search(name)).first
+      where_ilike(:name, normalize_name_for_search(name)).first
     else
       nil
     end

app/models/user.rb

@@ -139,7 +139,7 @@ class User < ApplicationRecord
 
       # XXX downcasing is the wrong way to do case-insensitive comparison for unicode (should use casefolding).
       def find_by_name(name)
-        where("lower(name) = ?", normalize_name(name)).first
+        where_ilike(:name, normalize_name(name)).first
       end
 
       def normalize_name(name)

db/migrate/20190902224045_fix_trigram_indexes_on_lower_names.rb

@@ -0,0 +1,23 @@
+class FixTrigramIndexesOnLowerNames < ActiveRecord::Migration[6.0]
+  def up
+    remove_index :posts, name: "index_posts_on_source_trgm"
+    add_index :posts, "source gin_trgm_ops", name: "index_posts_on_source_trgm", using: :gin
+
+    remove_index :users, name: "index_users_on_name_trgm"
+    add_index :users, "name gin_trgm_ops", name: "index_users_on_name_trgm", using: :gin
+
+    remove_index :pools, name: "index_pools_on_name_trgm"
+    add_index :pools, "name gin_trgm_ops", name: "index_pools_on_name_trgm", using: :gin
+  end
+
+  def down
+    remove_index :posts, name: "index_posts_on_source_trgm"
+    add_index :posts, "lower(source) gin_trgm_ops", name: "index_posts_on_source_trgm", using: :gin, where: "source != ''"
+
+    remove_index :users, name: "index_users_on_name_trgm"
+    add_index :users, "lower(name) gin_trgm_ops", name: "index_users_on_name_trgm", using: :gin
+
+    remove_index :pools, name: "index_pools_on_name_trgm"
+    add_index :pools, "lower(name) gin_trgm_ops", name: "index_pools_on_name_trgm", using: :gin
+  end
+end

db/structure.sql

@@ -6552,7 +6552,7 @@ CREATE INDEX index_pools_on_name ON public.pools USING btree (name);
 -- Name: index_pools_on_name_trgm; Type: INDEX; Schema: public; Owner: -
 --
 
-CREATE INDEX index_pools_on_name_trgm ON public.pools USING gin (lower((name)::text) public.gin_trgm_ops);
+CREATE INDEX index_pools_on_name_trgm ON public.pools USING gin (name public.gin_trgm_ops);
 
 
 --
@@ -6769,7 +6769,7 @@ CREATE INDEX index_posts_on_pixiv_id ON public.posts USING btree (pixiv_id) WHER
 -- Name: index_posts_on_source_trgm; Type: INDEX; Schema: public; Owner: -
 --
 
-CREATE INDEX index_posts_on_source_trgm ON public.posts USING gin (lower((source)::text) public.gin_trgm_ops) WHERE ((source)::text <> ''::text);
+CREATE INDEX index_posts_on_source_trgm ON public.posts USING gin (source public.gin_trgm_ops);
 
 
 --
@@ -7007,7 +7007,7 @@ CREATE UNIQUE INDEX index_users_on_name ON public.users USING btree (lower((name
 -- Name: index_users_on_name_trgm; Type: INDEX; Schema: public; Owner: -
 --
 
-CREATE INDEX index_users_on_name_trgm ON public.users USING gin (lower((name)::text) public.gin_trgm_ops);
+CREATE INDEX index_users_on_name_trgm ON public.users USING gin (name public.gin_trgm_ops);
 
 
 --
@@ -7315,6 +7315,7 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20190827234625'),
 ('20190828005453'),
 ('20190829052629'),
-('20190829055758');
+('20190829055758'),
+('20190902224045');
 
 

test/unit/pool_test.rb

@@ -52,6 +52,15 @@ class PoolTest < ActiveSupport::TestCase
     end
   end
 
+  context "Searching pools" do
+    should "find pools by name" do
+      @pool = FactoryBot.create(:pool, name: "Test Pool")
+
+      assert_equal(@pool.id, Pool.find_by_name("test pool").id)
+      assert_equal(@pool.id, Pool.search(name_matches: "test pool").first.id)
+    end
+  end
+
   context "Creating a pool" do
     setup do
       @posts = FactoryBot.create_list(:post, 5)