diff --git a/spec/performance/unique_job_on_conflict_replace_spec.rb b/spec/performance/unique_job_on_conflict_replace_spec.rb
new file mode 100644
index 000000000..2127396a1
--- /dev/null
+++ b/spec/performance/unique_job_on_conflict_replace_spec.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+# rubocop:disable RSpec/SpecFilePathFormat, RSpec/FilePath
+RSpec.describe UniqueJobOnConflictReplace, :perf do
+  let(:lock_prefix) { SidekiqUniqueJobs.config.lock_prefix }
+  let(:lock_timeout) { SidekiqUniqueJobs.config.lock_timeout }
+  let(:lock_ttl) { SidekiqUniqueJobs.config.lock_ttl }
+  let(:queue) { UniqueJobOnConflictReplace.sidekiq_options["queue"] }
+  let(:on_conflict) { UniqueJobOnConflictReplace.sidekiq_options["on_conflict"] }
+  let(:lock) { UniqueJobOnConflictReplace.sidekiq_options["lock"] }
+
+  before do
+    digests.delete_by_pattern("*")
+  end
+
+  context "when schedule queue is large" do
+    it "locks and replaces quickly" do
+      (0..100_000).each_slice(1_000) do |nums|
+        redis do |conn|
+          conn.pipelined do |pipeline|
+            nums.each do |num|
+              created_at   = Time.now.to_f
+              scheduled_at = created_at + rand(3_600..2_592_000)
+
+              payload = {
+                "retry" => true,
+                "queue" => queue,
+                "lock" => lock,
+                "on_conflict" => on_conflict,
+                "class" => described_class.name,
+                "args" => [num, { "type" => "extremely unique" }],
+                "jid" => SecureRandom.hex(12),
+                "created_at" => created_at,
+                "lock_timeout" => lock_timeout,
+                "lock_ttl" => lock_ttl,
+                "lock_prefix" => lock_prefix,
+                "lock_args" => [num, { "type" => "extremely unique" }],
+                "lock_digest" => "#{lock_prefix}:#{SecureRandom.hex}",
+              }
+
+              pipeline.zadd("schedule", scheduled_at, payload.to_json)
+            end
+          end
+        end
+      end
+
+      # queueing it once at the end of the queue should succeed
+      expect(described_class.perform_in(2_592_000, 100_000, { "type" => "extremely unique" })).to_not be_nil
+
+      # queueing it again should be performant
+      expect { described_class.perform_in(2_592_000, 100_000, { "type" => "extremely unique" }) }.to perform_under(10).ms
+    end
+  end
+end
diff --git a/spec/support/workers/unique_job_on_conflict_replace.rb b/spec/support/workers/unique_job_on_conflict_replace.rb
new file mode 100644
index 000000000..64c6a5631
--- /dev/null
+++ b/spec/support/workers/unique_job_on_conflict_replace.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# :nocov:
+
+class UniqueJobOnConflictReplace
+  include Sidekiq::Worker
+  sidekiq_options lock: :until_executing,
+                  queue: :customqueue,
+                  on_conflict: :replace
+
+  def perform(one, two)
+    [one, two]
+  end
+end
diff --git a/spec/workers/unique_job_on_conflict_replace_spec.rb b/spec/workers/unique_job_on_conflict_replace_spec.rb
new file mode 100644
index 000000000..6571ef440
--- /dev/null
+++ b/spec/workers/unique_job_on_conflict_replace_spec.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+RSpec.describe UniqueJobOnConflictReplace do
+  it_behaves_like "sidekiq with options" do
+    let(:options) do
+      {
+        "lock" => :until_executing,
+        "on_conflict" => :replace,
+        "queue" => :customqueue,
+        "retry" => true,
+      }
+    end
+  end
+
+  it_behaves_like "a performing worker" do
+    let(:args) { ["hundred", { "type" => "extremely unique", "id" => 44 }] }
+  end
+end