diff --git a/core/includes/database.inc b/core/includes/database.inc
index 6891ea92e1..3b6ce37a9b 100644
--- a/core/includes/database.inc
+++ b/core/includes/database.inc
@@ -181,9 +181,14 @@ function db_insert($table, array $options = []) {
  * @see \Drupal\Core\Database\Connection::defaultOptions()
  */
 function db_merge($table, array $options = []) {
+  // @todo Move defaults to connection https://www.drupal.org/node/2947775
   if (empty($options['target']) || $options['target'] == 'replica') {
     $options['target'] = 'default';
   }
+  @trigger_error(
+    "Deprecated as of Drupal 8.0.x, will be removed in Drupal 9.0.0. Instead, get a database connection injected into your service from the container and call merge() on it. For example, \$injected_database->merge(\$table, \$options);",
+    E_USER_DEPRECATED
+  );
   return Database::getConnection($options['target'])->merge($table, $options);
 }
 
diff --git a/core/modules/search/search.module b/core/modules/search/search.module
index 4b517c1cda..be665e6729 100644
--- a/core/modules/search/search.module
+++ b/core/modules/search/search.module
@@ -211,13 +211,14 @@ function search_cron() {
  * up to date (even if cron times out or otherwise fails).
  */
 function search_update_totals() {
+  $connection = \Drupal::database();
   // Update word IDF (Inverse Document Frequency) counts for new/changed words.
   foreach (search_dirty() as $word => $dummy) {
     // Get total count
     $total = db_query("SELECT SUM(score) FROM {search_index} WHERE word = :word", [':word' => $word], ['target' => 'replica'])->fetchField();
     // Apply Zipf's law to equalize the probability distribution.
     $total = log10(1 + 1 / (max(1, $total)));
-    \Drupal::database()->merge('search_total')
+    $connection->merge('search_total')
       ->key('word', $word)
       ->fields(['count' => $total])
       ->execute();
@@ -536,6 +537,7 @@ function search_index($type, $sid, $langcode, $text) {
   // cache tags.
   search_index_clear($type, $sid, $langcode);
 
+  $connection = \Drupal::database();
   // Insert cleaned up data into dataset
   db_insert('search_dataset')
     ->fields([
@@ -552,7 +554,7 @@ function search_index($type, $sid, $langcode, $text) {
     // If a word already exists in the database, its score gets increased
     // appropriately. If not, we create a new record with the appropriate
     // starting score.
-    \Drupal::database()->merge('search_index')
+    $connection->merge('search_index')
       ->keys([
         'word' => $word,
         'sid' => $sid,
diff --git a/core/modules/shortcut/src/ShortcutSetStorage.php b/core/modules/shortcut/src/ShortcutSetStorage.php
index ce0b442319..86d36a2a3d 100644
--- a/core/modules/shortcut/src/ShortcutSetStorage.php
+++ b/core/modules/shortcut/src/ShortcutSetStorage.php
@@ -71,6 +71,7 @@ public function deleteAssignedShortcutSets(ShortcutSetInterface $entity) {
    * {@inheritdoc}
    */
   public function assignUser(ShortcutSetInterface $shortcut_set, $account) {
+    // @todo Inject database service https://www.drupal.org/node/2947769
     \Drupal::database()->merge('shortcut_set_users')
       ->key('uid', $account->id())
       ->fields(['set_name' => $shortcut_set->id()])
diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index b18a232783..434a31f7ac 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -546,8 +546,9 @@ function taxonomy_build_node_index($node) {
     }
     // Insert index entries for all the node's terms.
     if (!empty($tid_all)) {
+      $connection = \Drupal::database();
       foreach ($tid_all as $tid) {
-        \Drupal::database()->merge('taxonomy_index')
+        $connection->merge('taxonomy_index')
           ->key(['nid' => $node->id(), 'tid' => $tid, 'status' => $node->isPublished()])
           ->fields(['sticky' => $sticky, 'created' => $node->getCreatedTime()])
           ->execute();
diff --git a/core/modules/tracker/tracker.module b/core/modules/tracker/tracker.module
index 86c37391f9..f129ad132e 100644
--- a/core/modules/tracker/tracker.module
+++ b/core/modules/tracker/tracker.module
@@ -259,7 +259,8 @@ function _tracker_add($nid, $uid, $changed) {
   $changed = max($node->changed, $changed);
 
   // Update the node-level data.
-  \Drupal::database()->merge('tracker_node')
+  $connection = \Drupal::database();
+  $connection->merge('tracker_node')
     ->key('nid', $nid)
     ->fields([
       'changed' => $changed,
@@ -268,7 +269,7 @@ function _tracker_add($nid, $uid, $changed) {
     ->execute();
 
   // Create or update the user-level data, first for the user posting.
-  \Drupal::database()->merge('tracker_user')
+  $connection->merge('tracker_user')
     ->keys([
       'nid' => $nid,
       'uid' => $uid,
diff --git a/core/tests/Drupal/KernelTests/Core/Database/MergeTest.php b/core/tests/Drupal/KernelTests/Core/Database/MergeTest.php
index 0b860f92c1..10e0ac852e 100644
--- a/core/tests/Drupal/KernelTests/Core/Database/MergeTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Database/MergeTest.php
@@ -18,6 +18,7 @@ class MergeTest extends DatabaseTestBase {
   public function testMergeInsert() {
     $num_records_before = db_query('SELECT COUNT(*) FROM {test_people}')->fetchField();
 
+    // @todo Inject database service https://www.drupal.org/node/2947769
     $result = \Drupal::database()->merge('test_people')
       ->key('job', 'Presenter')
       ->fields([
diff --git a/core/tests/Drupal/KernelTests/Core/Database/RegressionTest.php b/core/tests/Drupal/KernelTests/Core/Database/RegressionTest.php
index 22173dae66..3f8e2688d0 100644
--- a/core/tests/Drupal/KernelTests/Core/Database/RegressionTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Database/RegressionTest.php
@@ -3,6 +3,7 @@
 namespace Drupal\KernelTests\Core\Database;
 
 use Drupal\Core\Database\Database;
+use Drupal\Core\Database\Query\Merge;
 
 /**
  * Regression tests cases for the database layer.
@@ -59,6 +60,15 @@ public function testDBIndexExists() {
     $this->assertSame(FALSE, db_index_exists('test', 'nosuchindex'), 'Returns false for nonexistent index.');
   }
 
+  /**
+   * Tests the db_merge() function is deprecated.
+   *
+   * @expectedDeprecation Deprecated as of Drupal 8.0.x, will be removed in Drupal 9.0.0. Instead, get a database connection injected into your service from the container and call merge() on it. For example, $injected_database->merge($table, $options);
+   */
+  public function testDBMergeIsDeprecated() {
+    $this->assertTrue(db_merge('test') instanceof Merge);
+  }
+
   /**
    * Tests the db_set_active() function.
    *
diff --git a/core/tests/Drupal/KernelTests/Core/KeyValueStore/GarbageCollectionTest.php b/core/tests/Drupal/KernelTests/Core/KeyValueStore/GarbageCollectionTest.php
index 274093b7e3..e0107fc143 100644
--- a/core/tests/Drupal/KernelTests/Core/KeyValueStore/GarbageCollectionTest.php
+++ b/core/tests/Drupal/KernelTests/Core/KeyValueStore/GarbageCollectionTest.php
@@ -41,9 +41,10 @@ public function testGarbageCollection() {
     }
     $this->assertIdentical(count($store->getAll()), 4, 'Four items were written to the storage.');
 
+    $connection = \Drupal::database();
     // Manually expire the data.
     for ($i = 0; $i <= 3; $i++) {
-      \Drupal::database()->merge('key_value_expire')
+      $connection->merge('key_value_expire')
         ->keys([
             'name' => 'key_' . $i,
             'collection' => $collection,