Issue #3504902 by catch, berdir, kristiaanvandeneynde: Preload cache tags in cache getMultiple

core/lib/Drupal/Core/Cache/ApcuBackend.php

@@ -98,6 +98,18 @@ public function getMultiple(&$cids, $allow_invalid = FALSE) {
     $result = apcu_fetch(array_keys($map));
     $cache = [];
     if ($result) {
+      // Before checking the validity of each item individually, register the
+      // cache tags for all returned cache items for preloading, this allows the
+      // cache tag service to optimize cache tag lookups.
+      if ($this->checksumProvider instanceof CacheTagsChecksumPreloadInterface) {
+        $tags_for_preload = [];
+        foreach ($result as $item) {
+          if ($item->tags) {
+            $tags_for_preload[] = explode(' ', $item->tags);
+          }
+        }
+        $this->checksumProvider->registerCacheTagsForPreload(array_merge(...$tags_for_preload));
+      }
       foreach ($result as $key => $item) {
         $item = $this->prepareItem($item, $allow_invalid);
         if ($item) {

core/lib/Drupal/Core/Cache/CacheTagsChecksumTrait.php

@@ -182,7 +182,14 @@ public function reset() {
    * Implements \Drupal\Core\Cache\CacheTagsChecksumPreloadInterface::registerCacheTagsForPreload()
    */
   public function registerCacheTagsForPreload(array $cache_tags): void {
-    $this->preloadTags = array_merge($this->preloadTags, $cache_tags);
+    if (empty($cache_tags)) {
+      return;
+    }
+    // Don't preload delayed tags that are awaiting invalidation.
+    $preloadable_tags = array_diff($cache_tags, $this->delayedTags);
+    if ($preloadable_tags) {
+      $this->preloadTags = array_merge($this->preloadTags, $preloadable_tags);
+    }
   }
 
   /**

core/lib/Drupal/Core/Cache/DatabaseBackend.php

@@ -128,11 +128,23 @@ public function getMultiple(&$cids, $allow_invalid = FALSE) {
     // ::select() is a much smaller proportion of the request.
     $result = [];
     try {
-      $result = $this->connection->query('SELECT [cid], [data], [created], [expire], [serialized], [tags], [checksum] FROM {' . $this->connection->escapeTable($this->bin) . '} WHERE [cid] IN ( :cids[] ) ORDER BY [cid]', [':cids[]' => array_keys($cid_mapping)]);
+      $result = $this->connection->query('SELECT [cid], [data], [created], [expire], [serialized], [tags], [checksum] FROM {' . $this->connection->escapeTable($this->bin) . '} WHERE [cid] IN ( :cids[] ) ORDER BY [cid]', [':cids[]' => array_keys($cid_mapping)])->fetchAll();
     }
     catch (\Exception) {
       // Nothing to do.
     }
+    // Before checking the validity of each item individually, register the
+    // cache tags for all returned cache items for preloading, this allows the
+    // cache tag service to optimize cache tag lookups.
+    if ($this->checksumProvider instanceof CacheTagsChecksumPreloadInterface) {
+      $tags_for_preload = [];
+      foreach ($result as $item) {
+        if ($item->tags) {
+          $tags_for_preload[] = explode(' ', $item->tags);
+        }
+      }
+      $this->checksumProvider->registerCacheTagsForPreload(array_merge(...$tags_for_preload));
+    }
     $cache = [];
     foreach ($result as $item) {
       // Map the cache ID back to the original.

core/profiles/demo_umami/tests/src/FunctionalJavascript/OpenTelemetryAuthenticatedPerformanceTest.php

@@ -62,7 +62,7 @@ public function testFrontPageAuthenticatedWarmCache(): void {
       'CacheSetCount' => 0,
       'CacheDeleteCount' => 0,
       'CacheTagInvalidationCount' => 0,
-      'CacheTagLookupQueryCount' => 4,
+      'CacheTagLookupQueryCount' => 3,
       'ScriptCount' => 2,
       'ScriptBytes' => 123850,
       'StylesheetCount' => 2,