Add trigram index on snippet description

changelogs/unreleased/199220-snippet-index-desc.yml

+---
+title: Add trigram index on snippet description
+merge_request: 26341
+author:
+type: performance

db/migrate/20200303074328_add_index_on_snippet_description.rb

+# frozen_string_literal: true
+
+class AddIndexOnSnippetDescription < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  INDEX_NAME = 'index_snippets_on_description_trigram'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :snippets, :description, name: INDEX_NAME, using: :gin, opclass: { description: :gin_trgm_ops }
+  end
+
+  def down
+    remove_concurrent_index_by_name :snippets, INDEX_NAME
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_02_27_165129) do
+ActiveRecord::Schema.define(version: 2020_03_03_074328) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -3964,6 +3964,7 @@ ActiveRecord::Schema.define(version: 2020_02_27_165129) do
     t.index ["author_id"], name: "index_snippets_on_author_id"
     t.index ["content"], name: "index_snippets_on_content_trigram", opclass: :gin_trgm_ops, using: :gin
     t.index ["created_at"], name: "index_snippets_on_created_at"
+    t.index ["description"], name: "index_snippets_on_description_trigram", opclass: :gin_trgm_ops, using: :gin
     t.index ["file_name"], name: "index_snippets_on_file_name_trigram", opclass: :gin_trgm_ops, using: :gin
     t.index ["project_id", "visibility_level"], name: "index_snippets_on_project_id_and_visibility_level"
     t.index ["title"], name: "index_snippets_on_title_trigram", opclass: :gin_trgm_ops, using: :gin