Avoid duplicated queries and, instead, bump the last ones

app/controllers/searches_controller.rb

@@ -3,6 +3,6 @@ class SearchesController < ApplicationController
 
   def show
     @search_results = Current.user.search(@query_terms).limit(50)
-    @recent_search_queries = Current.user.search_queries.order(created_at: :desc).limit(50).uniq(&:terms)
+    @recent_search_queries = Current.user.search_queries.order(updated_at: :desc).limit(10)
   end
 end

app/models/user/searcher.rb

@@ -10,6 +10,8 @@ module User::Searcher
   end
 
   def remember_search(terms)
-    search_queries.create(terms: terms) if search_queries.last&.terms != terms
+    search_queries.find_or_create_by(terms: terms).tap do |search_query|
+      search_query.touch unless search_query.previously_new_record?
+    end
   end
 end

db/migrate/20250703193928_add_index_to_search_queries.rb

@@ -0,0 +1,5 @@
+class AddIndexToSearchQueries < ActiveRecord::Migration[8.1]
+  def change
+    add_index :search_queries, %w[ user_id updated_at ], unique: true
+  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[8.1].define(version: 2025_07_02_211937) do
+ActiveRecord::Schema[8.1].define(version: 2025_07_03_193928) do
   create_table "accesses", force: :cascade do |t|
     t.datetime "accessed_at"
     t.integer "collection_id", null: false
@@ -315,6 +315,7 @@ ActiveRecord::Schema[8.1].define(version: 2025_07_02_211937) do
     t.datetime "updated_at", null: false
     t.integer "user_id", null: false
     t.index ["user_id", "terms"], name: "index_search_queries_on_user_id_and_terms"
+    t.index ["user_id", "updated_at"], name: "index_search_queries_on_user_id_and_updated_at", unique: true
     t.index ["user_id"], name: "index_search_queries_on_user_id"
   end
 

db/schema_cache.yml

@@ -2312,6 +2312,23 @@ indexes:
     nulls_not_distinct:
     comment:
     valid: true
+  - !ruby/object:ActiveRecord::ConnectionAdapters::IndexDefinition
+    table: search_queries
+    name: index_search_queries_on_user_id_and_updated_at
+    unique: true
+    columns:
+    - user_id
+    - updated_at
+    lengths: {}
+    orders: {}
+    opclasses: {}
+    where:
+    type:
+    using:
+    include:
+    nulls_not_distinct:
+    comment:
+    valid: true
   search_results: []
   sessions:
   - !ruby/object:ActiveRecord::ConnectionAdapters::IndexDefinition
@@ -2499,4 +2516,4 @@ indexes:
     comment:
     valid: true
   workflows: []
-version: 20250702211937
+version: 20250703193928

script/remove_duplicated_search_queries.rb

@@ -0,0 +1,19 @@
+#!/usr/bin/env ruby
+
+require_relative "../config/environment"
+
+ApplicationRecord.with_each_tenant do |tenant|
+  User.find_each do |user|
+    search_queries = Set.new
+    to_delete = []
+    user.search_queries.find_each do |search_query|
+      if search_queries.include?(search_query.terms)
+        to_delete << search_query
+      end
+
+      search_queries << search_query.terms
+    end
+
+    to_delete.each(&:destroy)
+  end
+end

test/models/user/searcher_test.rb

@@ -13,11 +13,16 @@ class User::SearcherTest < ActiveSupport::TestCase
     assert_equal "broken", @user.search_queries.last.terms
   end
 
-  test "don't duplicate repeated searches" do
-    @user.remember_search("broken")
+  test "don't duplicate repeated searches but touch the existing match" do
+    search_result = @user.remember_search("broken")
+    original_updated_at = search_result.updated_at
+
+    travel_to 1.day.from_now
 
     assert_no_difference -> { @user.search_queries.count }, +1 do
       @user.remember_search("broken")
     end
+
+    assert search_result.reload.updated_at > original_updated_at
   end
 end