diff --git a/lib/app_generator/search_app.rb b/lib/app_generator/search_app.rb
index 5ac973b0a..553db1bbf 100644
--- a/lib/app_generator/search_app.rb
+++ b/lib/app_generator/search_app.rb
@@ -25,6 +25,7 @@ class SearchApp < App
                   :persistence_threads => :persistence_threads,
                   :cpu_socket_affinity => :cpu_socket_affinity,
                   :resource_limits => :resource_limits,
+                  :posting_list_cache => :posting_list_cache,
                   :proton_resource_limits => :proton_resource_limits,
                   :search_io => :search_io,
                   :indexing_cluster => :indexing_cluster,
diff --git a/lib/app_generator/search_cluster.rb b/lib/app_generator/search_cluster.rb
index be1e3072f..62afee9a7 100644
--- a/lib/app_generator/search_cluster.rb
+++ b/lib/app_generator/search_cluster.rb
@@ -29,6 +29,7 @@ class SearchCluster
   chained_setter :min_node_ratio_per_group
   chained_setter :persistence_threads
   chained_setter :resource_limits
+  chained_setter :posting_list_cache
   chained_setter :proton_resource_limits
   chained_setter :search_io
   chained_forward :config, :config => :add
@@ -69,6 +70,7 @@ def initialize(name = "search")
     @hwinfo_disk_shared = true
     @persistence_threads = nil
     @resource_limits = nil
+    @posting_list_cache = nil
     @proton_resource_limits = nil
     @search_io = nil
   end
@@ -155,6 +157,9 @@ def proton_config(indent)
     unless @search_io.nil?
       proton.add('search', ConfigValue.new('io', @search_io))
     end
+    unless @posting_list_cache.nil?
+      proton.add('index', ConfigValue.new('postinglist', ConfigValue.new('cache', ConfigValue.new('maxbytes', @posting_list_cache))))
+    end
     XmlHelper.new(indent).to_xml(proton)
   end
 
diff --git a/lib/app_generator/test/test.rb b/lib/app_generator/test/test.rb
index 12dda2d91..c852cbeb9 100644
--- a/lib/app_generator/test/test.rb
+++ b/lib/app_generator/test/test.rb
@@ -729,6 +729,21 @@ def test_that_search_io_can_be_specified
     assert_substring_ignore_whitespace(actual, expected_config_fragment)
   end
 
+  def test_that_posting_list_cache_can_be_specified
+    actual = SearchApp.new.posting_list_cache(12345).services_xml
+
+    expected_config_fragment='
+      <index>
+        <postinglist>
+          <cache>
+            <maxbytes>12345</maxbytes>
+          </cache>
+        </postinglist>
+      </index>'
+
+    assert_substring_ignore_whitespace(actual, expected_config_fragment)
+  end
+
   def test_doc_api_and_feeder_options
     actual = SearchApp.new.enable_document_api(FeederOptions.new.timeout(40)).services_xml
 
diff --git a/tests/search/metrics/metrics.rb b/tests/search/metrics/metrics.rb
index 39c7d8265..e4be63a5f 100644
--- a/tests/search/metrics/metrics.rb
+++ b/tests/search/metrics/metrics.rb
@@ -18,7 +18,7 @@ def test_metrics
                       tune_searchnode({:summary => {:store => {:cache => { :maxsize => 8192,
                                                                            :compression => {:type => :lz4, :level => 8}
                                                                          } } } }).
-                 search_io('DIRECTIO')))
+                 search_io('DIRECTIO').posting_list_cache(262144)))
     start
 
     # Search handler does a warmup query which may or may not hit the backend, since 8.170. We need to account for this in some search metrics below. 
@@ -89,6 +89,11 @@ def test_metrics
     metrics = vespa.search['test'].first.get_total_metrics # Get metrics containing disk index
     assert_document_db_size_on_disk(metrics)
     assert_document_db_disk_io(metrics)
+    assert_document_db_cached_disk_io(metrics, false)
+    assert_hitcount("f1:c", 2)
+    metrics = vespa.search['test'].first.get_total_metrics # Get metrics containing disk index
+    assert_document_db_disk_io(metrics)
+    assert_document_db_cached_disk_io(metrics, true)
   end
 
   def test_metrics_imported_attributes
@@ -185,6 +190,18 @@ def assert_document_db_disk_io(metrics)
     assert(0 < f1_disk_io["count"])
   end
 
+  def assert_document_db_cached_disk_io(metrics, expect_cached)
+    f1_cached_disk_io = get_cached_disk_io_for_field('f1', metrics)
+    puts "f1_cached_disk_io = " + f1_cached_disk_io.to_s
+    if expect_cached
+      assert(1000 < f1_cached_disk_io["sum"])
+      assert(0 < f1_cached_disk_io["count"])
+    else
+      assert_equal(0, f1_cached_disk_io["sum"])
+      assert_equal(0, f1_cached_disk_io["count"])
+    end
+  end
+
   def get_size_on_disk_for_field(field_name, metrics)
     metrics.get('content.proton.documentdb.ready.index.size_on_disk',
                 {"documenttype" => "test", "field" => field_name})["last"]
@@ -196,6 +213,11 @@ def get_disk_io_for_field(field_name, metrics)
                 {"documenttype" => "test", "field" => field_name})
   end
 
+  def get_cached_disk_io_for_field(field_name, metrics)
+    metrics.get('content.proton.documentdb.ready.index.io.search.cached_read_bytes',
+                {"documenttype" => "test", "field" => field_name})
+  end
+
   def dump_metric_names(metrics)
     metrics.json["values"].each do |metric|
       name = metric["name"]