diff --git a/core/Application.php b/core/Application.php
index 2e354610154..592e0929666 100644
--- a/core/Application.php
+++ b/core/Application.php
@@ -243,6 +243,13 @@ class Application extends App {
 						$subject->addHintForMissingSubject($table->getName(), 'mounts_user_root_path_index');
 					}
 				}
+
+				if ($schema->hasTable('systemtag_object_mapping')) {
+					$table = $schema->getTable('systemtag_object_mapping');
+					if (!$table->hasIndex('systag_by_tagid')) {
+						$subject->addHintForMissingSubject($table->getName(), 'systag_by_tagid');
+					}
+				}
 			}
 		);
 
diff --git a/core/Command/Db/AddMissingIndices.php b/core/Command/Db/AddMissingIndices.php
index b317f44b499..452bcbad5dc 100644
--- a/core/Command/Db/AddMissingIndices.php
+++ b/core/Command/Db/AddMissingIndices.php
@@ -475,6 +475,19 @@ class AddMissingIndices extends Command {
 			}
 		}
 
+		$output->writeln('<info>Check indices of the oc_systemtag_object_mapping table.</info>');
+		if ($schema->hasTable('oc_systemtag_object_mapping')) {
+			$table = $schema->getTable('oc_systemtag_object_mapping');
+			if (!$table->hasIndex('systag_by_tagid')) {
+				$output->writeln('<info>Adding systag_by_tagid index to the oc_systemtag_object_mapping table, this can take some time...</info>');
+
+				$table->addIndex(['systemtagid', 'objecttype'], 'systag_by_tagid');
+				$this->connection->migrateToSchema($schema->getWrappedSchema());
+				$updated = true;
+				$output->writeln('<info>oc_systemtag_object_mapping table updated successfully.</info>');
+			}
+		}
+
 		if (!$updated) {
 			$output->writeln('<info>Done.</info>');
 		}
diff --git a/core/Migrations/Version28000Date20230621185127.php b/core/Migrations/Version28000Date20230621185127.php
new file mode 100644
index 00000000000..eb656bb89df
--- /dev/null
+++ b/core/Migrations/Version28000Date20230621185127.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2023 Marcel Klehr <mklehr@gmx.net>
+ *
+ * @author Marcel Klehr <mklehr@gmx.net>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OC\Core\Migrations;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version28000Date20230621185127 extends SimpleMigrationStep {
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$table = $schema->getTable('systemtag_object_mapping');
+		if (!$table->hasIndex('systag_by_tagid')) {
+			$table->addIndex(['systemtagid', 'objecttype'], 'systag_by_tagid');
+			return $schema;
+		}
+
+		return null;
+	}
+}