Improve the search speed

Add tsvactor_column to store the tsvector - content in the database. This speeds up the search speed on large table, because these value isn't calculated on fly anymore. A dictionary configuration to allow to setup the used PostgreSQL dictionary.

README.md

@@ -24,6 +24,12 @@ Run install script:
 $ bin/rails g alchemy:pg_search:install
 ```
 
+> [!NOTE]  
+> The installation will generate an autogenerated column which can be configured with a language. The default
+> value should work for the most languages. If you wish to change this behavior you should add
+> the `Alchemy::PgSearch.config`
+> into the project initializer before running the install script. (See [Configure Behavior](#configure-behavior))
+
 ## Usage
 
 Every `Ingredient` will be indexed unless you tell Alchemy to not index a specific content.
@@ -88,10 +94,16 @@ Configure the gem in an initializer. The default configurations are:
 
 ```ruby
 Alchemy::PgSearch.config = {
-  paginate_per: 10, # amount of results per page
+  dictionary: 'simple',
+  paginate_per: 10
 }
 ```
 
+ Configuration Name | Default Value | Description                                                                                                                                                                                                                                                                                                 
+--------------------|---------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ dictionary         | simple        | Dictionary for the multisearch tsearch - config, which is used to find the content. The dictionary can impact the amout found documents, because it removes language specific stop words. See more in the [PostgreSQL documentation](https://www.postgresql.org/docs/current/textsearch-dictionaries.html). 
+ paginate_per       | 10            | Amount of results per page. The value can be set to `nil` to disable the pagination.                                                                                                                                                                                                                        
+
 You can also overwrite the default multisearch configuration to use other search strategies. For more information take
 a look into the [PgSearch Readme](https://github.com/Casecommons/pg_search#configuring-multi-search).
 
@@ -107,7 +119,8 @@ end
 
 ### Rendering search results.
 
-In order to render the search results, you'll need a page layout that represents the search result page. Simply mark a page layout as `searchresults: true`. The search form will pick this page as result page.
+In order to render the search results, you'll need a page layout that represents the search result page. Simply mark a
+page layout as `searchresults: true`. The search form will pick this page as result page.
 
 #### Search Results Page
 
@@ -118,24 +131,26 @@ In order to render the search results, you'll need a page layout that represents
   unique: true
 ```
 
-Tip: For maximum flexibility you could also add an element that represents the search results. This lets your editors to place additional elements (maybe a header image or additional text blocks) on the search result page.
+Tip: For maximum flexibility you could also add an element that represents the search results. This lets your editors to
+place additional elements (maybe a header image or additional text blocks) on the search result page.
 
 ```yaml
 # page_layouts.yml
 - name: search
   searchresults: true
   unique: true
   elements:
-  - searchresults
+    - searchresults
   autogenerate:
-  - searchresults
+    - searchresults
 
 # elements.yml
 - name: searchresults
   unique: true
 ```
 
-and then use the view helpers to render the search form on the page layout partial and the search results on the element view partial.
+and then use the view helpers to render the search form on the page layout partial and the search results on the element
+view partial.
 
 ### View Helpers
 

db/migrate/20231218165617_add_searchable_content.rb

@@ -0,0 +1,16 @@
+class AddSearchableContent < ActiveRecord::Migration[6.0]
+  def up
+    unless column_exists? :pg_search_documents, :searchable_content
+      execute %|ALTER TABLE pg_search_documents
+        ADD COLUMN searchable_content tsvector GENERATED ALWAYS AS (
+          to_tsvector('#{Alchemy::PgSearch.config[:dictionary]}', coalesce(content, ''))
+        ) STORED;|
+    end
+  end
+
+  def down
+    if column_exists? :pg_search_documents, :searchable_content
+      remove_column :pg_search_documents, :searchable_content
+    end
+  end
+end

lib/alchemy/pg_search/config.rb

@@ -2,6 +2,7 @@ module Alchemy
   module PgSearch
     module Config
       @@config = {
+        dictionary: 'simple',
         paginate_per: 10
       }
 

lib/alchemy/pg_search/engine.rb

@@ -24,7 +24,11 @@ class Engine < ::Rails::Engine
         # @link https://github.com/Casecommons/pg_search#searching-using-different-search-features
         ::PgSearch.multisearch_options = {
           using: {
-            tsearch: { prefix: true }
+            tsearch: {
+              prefix: true,
+              dictionary: Alchemy::PgSearch.config[:dictionary],
+              tsvector_column: 'searchable_content'
+            }
           }
         }
       end

spec/dummy/db/migrate/20231218165617_add_searchable_content.rb

@@ -0,0 +1,16 @@
+class AddSearchableContent < ActiveRecord::Migration[6.0]
+  def up
+    unless column_exists? :pg_search_documents, :searchable_content
+      execute %|ALTER TABLE pg_search_documents
+        ADD COLUMN searchable_content tsvector GENERATED ALWAYS AS (
+          to_tsvector('#{Alchemy::PgSearch.config[:dictionary]}', coalesce(content, ''))
+        ) STORED;|
+    end
+  end
+
+  def down
+    if column_exists? :pg_search_documents, :searchable_content
+      remove_column :pg_search_documents, :searchable_content
+    end
+  end
+end

spec/dummy/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2023_07_24_074129) do
+ActiveRecord::Schema[7.0].define(version: 2023_12_18_165617) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -376,6 +376,7 @@
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.bigint "page_id"
+    t.virtual "searchable_content", type: :tsvector, as: "to_tsvector('simple'::regconfig, COALESCE(content, ''::text))", stored: true
     t.index ["page_id"], name: "index_pg_search_documents_on_page_id"
     t.index ["searchable_type", "searchable_id"], name: "index_pg_search_documents_on_searchable_type_and_searchable_id"
   end