Avoid N+1 queries problem

src/library/entry.cr

@@ -72,7 +72,7 @@ class Entry
   def sort_title
     sort_title_cached = @sort_title
     return sort_title_cached if sort_title_cached
-    sort_title = Storage.default.get_entry_sort_title id
+    sort_title = @book.entry_sort_title_db id
     if sort_title
       @sort_title = sort_title
       return sort_title
@@ -89,11 +89,12 @@ class Entry
       @sort_title = sort_title
     end
 
+    @book.entry_sort_title_cache = nil
     @book.remove_sorted_caches [SortMethod::Auto, SortMethod::Title], username
   end
 
   def sort_title_db
-    Storage.default.get_entry_sort_title id
+    @book.entry_sort_title_db @id
   end
 
   def display_name

src/library/title.cr

@@ -8,11 +8,14 @@ class Title
     entries : Array(Entry), title : String, id : String,
     encoded_title : String, mtime : Time, signature : UInt64,
     entry_cover_url_cache : Hash(String, String)?
-  setter entry_cover_url_cache : Hash(String, String)?
+  setter entry_cover_url_cache : Hash(String, String)?,
+    entry_sort_title_cache : Hash(String, String | Nil)?
 
   @[YAML::Field(ignore: true)]
   @sort_title : String?
   @[YAML::Field(ignore: true)]
+  @entry_sort_title_cache : Hash(String, String | Nil)?
+  @[YAML::Field(ignore: true)]
   @entry_display_name_cache : Hash(String, String)?
   @[YAML::Field(ignore: true)]
   @entry_cover_url_cache : Hash(String, String)?
@@ -324,6 +327,15 @@ class Title
     Storage.default.get_title_sort_title id
   end
 
+  def entry_sort_title_db(entry_id)
+    unless @entry_sort_title_cache
+      @entry_sort_title_cache =
+        Storage.default.get_entries_sort_title @entries.map &.id
+    end
+
+    @entry_sort_title_cache.not_nil![entry_id]?
+  end
+
   def tags
     Storage.default.get_title_tags @id
   end

src/storage.cr

@@ -371,6 +371,22 @@ class Storage
     sort_title
   end
 
+  def get_entries_sort_title(ids : Array(String))
+    results = Hash(String, String | Nil).new
+    MainFiber.run do
+      get_db do |db|
+        db.query "select id, sort_title from ids where id in (#{ids.join "," { |id| "'#{id}'" }})" do |rs|
+          rs.each do
+            id = rs.read String
+            sort_title = rs.read String | Nil
+            results[id] = sort_title
+          end
+        end
+      end
+    end
+    results
+  end
+
   def set_entry_sort_title(entry_id : String, sort_title : String | Nil)
     sort_title = nil if sort_title == ""
     MainFiber.run do