diff --git a/core/CHANGELOG.txt b/core/CHANGELOG.txt
index 98f9108..244d0f0 100644
--- a/core/CHANGELOG.txt
+++ b/core/CHANGELOG.txt
@@ -134,8 +134,8 @@ Drupal 7.0, 2011-01-05
     * Fully rewritten database layer utilizing PHP 5's PDO abstraction layer.
     * Drupal now requires MySQL >= 5.0.15 or PostgreSQL >= 8.3.
     * Added query builders for INSERT, UPDATE, DELETE, MERGE, and SELECT queries.
-    * Support for master/slave replication, transactions, multi-insert queries,
-      and other features.
+    * Support for primary/secondary replication, transactions, multi-insert
+      queries, and other features.
     * Added support for the SQLite database engine.
     * Default to InnoDB engine, rather than MyISAM, on MySQL when available.
       This offers increased scalability and data integrity.
diff --git a/core/core.services.yml b/core/core.services.yml
index d0facb4..e4eadfa 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -307,11 +307,11 @@ services:
       - [initLanguageManager]
     tags:
       - { name: service_collector, tag: string_translator, call: addTranslator }
-  database.slave:
+  database.secondary:
     class: Drupal\Core\Database\Connection
     factory_class: Drupal\Core\Database\Database
     factory_method: getConnection
-    arguments: [slave]
+    arguments: [secondary]
   typed_data_manager:
     class: Drupal\Core\TypedData\TypedDataManager
     parent: default_plugin_manager
@@ -706,8 +706,8 @@ services:
   batch.storage:
     class: Drupal\Core\Batch\BatchStorage
     arguments: ['@database']
-  slave_database_ignore__subscriber:
-    class: Drupal\Core\EventSubscriber\SlaveDatabaseIgnoreSubscriber
+  secondary_database_ignore__subscriber:
+    class: Drupal\Core\EventSubscriber\SecondaryDatabaseIgnoreSubscriber
     tags:
       - {name: event_subscriber}
   country_manager:
diff --git a/core/includes/database.inc b/core/includes/database.inc
index e1f4f30..22c10e0 100644
--- a/core/includes/database.inc
+++ b/core/includes/database.inc
@@ -296,7 +296,7 @@ function db_query_temporary($query, array $args = array(), array $options = arra
  *   A new Insert object for this connection.
  */
 function db_insert($table, array $options = array()) {
-  if (empty($options['target']) || $options['target'] == 'slave') {
+  if (empty($options['target']) || $options['target'] == 'secondary') {
     $options['target'] = 'default';
   }
   return Database::getConnection($options['target'])->insert($table, $options);
@@ -314,7 +314,7 @@ function db_insert($table, array $options = array()) {
  *   A new Merge object for this connection.
  */
 function db_merge($table, array $options = array()) {
-  if (empty($options['target']) || $options['target'] == 'slave') {
+  if (empty($options['target']) || $options['target'] == 'secondary') {
     $options['target'] = 'default';
   }
   return Database::getConnection($options['target'])->merge($table, $options);
@@ -332,7 +332,7 @@ function db_merge($table, array $options = array()) {
  *   A new Update object for this connection.
  */
 function db_update($table, array $options = array()) {
-  if (empty($options['target']) || $options['target'] == 'slave') {
+  if (empty($options['target']) || $options['target'] == 'secondary') {
     $options['target'] = 'default';
   }
   return Database::getConnection($options['target'])->update($table, $options);
@@ -350,7 +350,7 @@ function db_update($table, array $options = array()) {
  *   A new Delete object for this connection.
  */
 function db_delete($table, array $options = array()) {
-  if (empty($options['target']) || $options['target'] == 'slave') {
+  if (empty($options['target']) || $options['target'] == 'secondary') {
     $options['target'] = 'default';
   }
   return Database::getConnection($options['target'])->delete($table, $options);
@@ -368,7 +368,7 @@ function db_delete($table, array $options = array()) {
  *   A new Truncate object for this connection.
  */
 function db_truncate($table, array $options = array()) {
-  if (empty($options['target']) || $options['target'] == 'slave') {
+  if (empty($options['target']) || $options['target'] == 'secondary') {
     $options['target'] = 'default';
   }
   return Database::getConnection($options['target'])->truncate($table, $options);
@@ -924,18 +924,19 @@ function db_change_field($table, $field, $field_new, $spec, $keys_new = array())
  */
 
 /**
- * Sets a session variable specifying the lag time for ignoring a slave server.
+ * Sets a session variable specifying the lag time for ignoring a secondary
+ * server.
  */
-function db_ignore_slave() {
+function db_ignore_secondary() {
   $connection_info = Database::getConnectionInfo();
-  // Only set ignore_slave_server if there are slave servers being used, which
-  // is assumed if there are more than one.
+  // Only set ignore_secondary_server if there are secondary servers being used,
+  // which is assumed if there are more than one.
   if (count($connection_info) > 1) {
-    // Five minutes is long enough to allow the slave to break and resume
+    // Five minutes is long enough to allow the secondary to break and resume
     // interrupted replication without causing problems on the Drupal site from
     // the old data.
     $duration = Settings::get('maximum_replication_lag', 300);
-    // Set session variable with amount of time to delay before using slave.
-    $_SESSION['ignore_slave_server'] = REQUEST_TIME + $duration;
+    // Set session variable with amount of time to delay before using secondary.
+    $_SESSION['ignore_secondary_server'] = REQUEST_TIME + $duration;
   }
 }
diff --git a/core/lib/Drupal/Core/Config/DatabaseStorage.php b/core/lib/Drupal/Core/Config/DatabaseStorage.php
index 99c638e..b1ebbf0 100644
--- a/core/lib/Drupal/Core/Config/DatabaseStorage.php
+++ b/core/lib/Drupal/Core/Config/DatabaseStorage.php
@@ -219,7 +219,7 @@ protected static function schemaDefinition() {
    *
    * @throws PDOException
    *
-   * @todo Ignore slave targets for data manipulation operations.
+   * @todo Ignore secondary targets for data manipulation operations.
    */
   public function delete($name) {
     $options = array('return' => Database::RETURN_AFFECTED) + $this->options;
diff --git a/core/lib/Drupal/Core/Database/Connection.php b/core/lib/Drupal/Core/Database/Connection.php
index 6e87303..c167f0c 100644
--- a/core/lib/Drupal/Core/Database/Connection.php
+++ b/core/lib/Drupal/Core/Database/Connection.php
@@ -35,8 +35,8 @@
    * The key representing this connection.
    *
    * The key is a unique string which identifies a database connection. A
-   * connection can be a single server or a cluster of master and slaves (use
-   * target to pick between master and slave).
+   * connection can be a single server or a cluster of primary and secondaries (use
+   * target to pick between primary and secondary).
    *
    * @var string
    */
@@ -188,7 +188,7 @@ public function destroy() {
    * A given query can be customized with a number of option flags in an
    * associative array:
    * - target: The database "target" against which to execute a query. Valid
-   *   values are "default" or "slave". The system will first try to open a
+   *   values are "default" or "secondary". The system will first try to open a
    *   connection to a database specified with the user-supplied key. If one
    *   is not available, it will silently fall back to the "default" target.
    *   If multiple databases connections are specified with the same target,
diff --git a/core/lib/Drupal/Core/Database/Database.php b/core/lib/Drupal/Core/Database/Database.php
index 4a6fb06..63170d8 100644
--- a/core/lib/Drupal/Core/Database/Database.php
+++ b/core/lib/Drupal/Core/Database/Database.php
@@ -159,8 +159,8 @@
     }
     // If the requested target does not exist, or if it is ignored, we fall back
     // to the default target. The target is typically either "default" or
-    // "slave", indicating to use a slave SQL server if one is available. If
-    // it's not available, then the default/master server is the correct server
+    // "secondary", indicating to use a secondary SQL server if one is available. If
+    // it's not available, then the default/primary server is the correct server
     // to use.
     if (!empty(self::$ignoreTargets[$key][$target]) || !isset(self::$databaseInfo[$key][$target])) {
       $target = 'default';
@@ -212,7 +212,7 @@
   final public static function parseConnectionInfo(array $info) {
     // If there is no "driver" property, then we assume it's an array of
     // possible connections for this target. Pick one at random. That allows
-    // us to have, for example, multiple slave servers.
+    // us to have, for example, multiple secondary servers.
     if (empty($info['driver'])) {
       $info = $info[mt_rand(0, count($info) - 1)];
     }
@@ -431,7 +431,7 @@ public static function closeConnection($target = NULL, $key = NULL) {
   /**
    * Instructs the system to temporarily ignore a given key/target.
    *
-   * At times we need to temporarily disable slave queries. To do so, call this
+   * At times we need to temporarily disable secondary queries. To do so, call this
    * method with the database key and the target to disable. That database key
    * will then always fall back to 'default' for that key, even if it's defined.
    *
diff --git a/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php b/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
index ce186be..1afb52b 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
@@ -611,8 +611,8 @@ public function delete(array $entities) {
     try {
       parent::delete($entities);
 
-      // Ignore slave server temporarily.
-      db_ignore_slave();
+      // Ignore secondary server temporarily.
+      db_ignore_secondary();
     }
     catch (\Exception $e) {
       $transaction->rollback();
@@ -669,8 +669,8 @@ public function save(EntityInterface $entity) {
 
       $return = parent::save($entity);
 
-      // Ignore slave server temporarily.
-      db_ignore_slave();
+      // Ignore secondary server temporarily.
+      db_ignore_secondary();
       return $return;
     }
     catch (\Exception $e) {
diff --git a/core/lib/Drupal/Core/Entity/EntityDatabaseStorage.php b/core/lib/Drupal/Core/Entity/EntityDatabaseStorage.php
index 7a4316b..88431f9 100644
--- a/core/lib/Drupal/Core/Entity/EntityDatabaseStorage.php
+++ b/core/lib/Drupal/Core/Entity/EntityDatabaseStorage.php
@@ -135,8 +135,8 @@ public function delete(array $entities) {
     try {
       parent::delete($entities);
 
-      // Ignore slave server temporarily.
-      db_ignore_slave();
+      // Ignore secondary server temporarily.
+      db_ignore_secondary();
     }
     catch (\Exception $e) {
       $transaction->rollback();
@@ -167,8 +167,8 @@ public function save(EntityInterface $entity) {
     try {
       $return = parent::save($entity);
 
-      // Ignore slave server temporarily.
-      db_ignore_slave();
+      // Ignore secondary server temporarily.
+      db_ignore_secondary();
       return $return;
     }
     catch (\Exception $e) {
diff --git a/core/lib/Drupal/Core/EventSubscriber/SecondaryDatabaseIgnoreSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/SecondaryDatabaseIgnoreSubscriber.php
new file mode 100644
index 0000000..c848fb9
--- /dev/null
+++ b/core/lib/Drupal/Core/EventSubscriber/SecondaryDatabaseIgnoreSubscriber.php
@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\EventSubscriber\SecondaryDatabaseIgnoreSubscriber.
+ */
+
+namespace Drupal\Core\EventSubscriber;
+
+use Drupal\Core\Database\Database;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * System subscriber for controller requests.
+ */
+class SecondaryDatabaseIgnoreSubscriber implements EventSubscriberInterface {
+
+  /**
+   * Checks and disables the secondary database server if appropriate.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
+   *   The Event to process.
+   */
+  public function checkSecondaryServer(GetResponseEvent $event) {
+    // Ignore secondary database servers for this request.
+    //
+    // In Drupal's distributed database structure, new data is written to the
+    // master and then propagated to the secondary servers.  This means there is a
+    // lag between when data is written to the master and when it is available
+    // on the secondary. At these times, we will want to avoid using a secondary server
+    // temporarily. For example, if a user posts a new node then we want to
+    // disable the secondary server for that user temporarily to allow the secondary
+    // server to catch up.
+    // That way, that user will see their changes immediately while for other
+    // users we still get the benefits of having a secondary server, just with
+    // slightly stale data.  Code that wants to disable the secondary server should
+    // use the db_set_ignore_secondary() function to set
+    // $_SESSION['ignore_secondary_server'] to the timestamp after which the secondary
+    // can be re-enabled.
+    if (isset($_SESSION['ignore_secondary_server'])) {
+      if ($_SESSION['ignore_secondary_server'] >= REQUEST_TIME) {
+        Database::ignoreTarget('default', 'secondary');
+      }
+      else {
+        unset($_SESSION['ignore_secondary_server']);
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  static function getSubscribedEvents() {
+    $events[KernelEvents::REQUEST][] = array('checkSecondaryServer');
+    return $events;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/EventSubscriber/SlaveDatabaseIgnoreSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/SlaveDatabaseIgnoreSubscriber.php
deleted file mode 100644
index e10ce04..0000000
--- a/core/lib/Drupal/Core/EventSubscriber/SlaveDatabaseIgnoreSubscriber.php
+++ /dev/null
@@ -1,60 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\EventSubscriber\SlaveDatabaseIgnoreSubscriber.
- */
-
-namespace Drupal\Core\EventSubscriber;
-
-use Drupal\Core\Database\Database;
-use Symfony\Component\HttpKernel\KernelEvents;
-use Symfony\Component\HttpKernel\Event\GetResponseEvent;
-use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-
-/**
- * System subscriber for controller requests.
- */
-class SlaveDatabaseIgnoreSubscriber implements EventSubscriberInterface {
-
-  /**
-   * Checks and disables the slave database server if appropriate.
-   *
-   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
-   *   The Event to process.
-   */
-  public function checkSlaveServer(GetResponseEvent $event) {
-    // Ignore slave database servers for this request.
-    //
-    // In Drupal's distributed database structure, new data is written to the
-    // master and then propagated to the slave servers.  This means there is a
-    // lag between when data is written to the master and when it is available
-    // on the slave. At these times, we will want to avoid using a slave server
-    // temporarily. For example, if a user posts a new node then we want to
-    // disable the slave server for that user temporarily to allow the slave
-    // server to catch up.
-    // That way, that user will see their changes immediately while for other
-    // users we still get the benefits of having a slave server, just with
-    // slightly stale data.  Code that wants to disable the slave server should
-    // use the db_set_ignore_slave() function to set
-    // $_SESSION['ignore_slave_server'] to the timestamp after which the slave
-    // can be re-enabled.
-    if (isset($_SESSION['ignore_slave_server'])) {
-      if ($_SESSION['ignore_slave_server'] >= REQUEST_TIME) {
-        Database::ignoreTarget('default', 'slave');
-      }
-      else {
-        unset($_SESSION['ignore_slave_server']);
-      }
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  static function getSubscribedEvents() {
-    $events[KernelEvents::REQUEST][] = array('checkSlaveServer');
-    return $events;
-  }
-
-}
diff --git a/core/modules/aggregator/config/install/views.view.aggregator_rss_feed.yml b/core/modules/aggregator/config/install/views.view.aggregator_rss_feed.yml
index c4caa75..1c7ad51 100644
--- a/core/modules/aggregator/config/install/views.view.aggregator_rss_feed.yml
+++ b/core/modules/aggregator/config/install/views.view.aggregator_rss_feed.yml
@@ -23,7 +23,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/comment/tests/modules/comment_test_views/test_views/views.view.test_comment_row.yml b/core/modules/comment/tests/modules/comment_test_views/test_views/views.view.test_comment_row.yml
index c2de92e..4c1afe9 100644
--- a/core/modules/comment/tests/modules/comment_test_views/test_views/views.view.test_comment_row.yml
+++ b/core/modules/comment/tests/modules/comment_test_views/test_views/views.view.test_comment_row.yml
@@ -29,7 +29,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
       exposed_form:
diff --git a/core/modules/contact/tests/modules/contact_test_views/test_views/views.view.test_contact_link.yml b/core/modules/contact/tests/modules/contact_test_views/test_views/views.view.test_contact_link.yml
index e060a63..471024c 100644
--- a/core/modules/contact/tests/modules/contact_test_views/test_views/views.view.test_contact_link.yml
+++ b/core/modules/contact/tests/modules/contact_test_views/test_views/views.view.test_contact_link.yml
@@ -20,7 +20,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: ''
           query_tags: {  }
       exposed_form:
diff --git a/core/modules/file/config/install/views.view.files.yml b/core/modules/file/config/install/views.view.files.yml
index 2d65909..160db69 100644
--- a/core/modules/file/config/install/views.view.files.yml
+++ b/core/modules/file/config/install/views.view.files.yml
@@ -24,7 +24,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/menu_link/src/MenuLinkStorage.php b/core/modules/menu_link/src/MenuLinkStorage.php
index 60871d0..140bfdc 100644
--- a/core/modules/menu_link/src/MenuLinkStorage.php
+++ b/core/modules/menu_link/src/MenuLinkStorage.php
@@ -95,8 +95,8 @@ public function save(EntityInterface $entity) {
         }
       }
 
-      // Ignore slave server temporarily.
-      db_ignore_slave();
+      // Ignore secondary server temporarily.
+      db_ignore_secondary();
       unset($entity->original);
 
       return $return;
diff --git a/core/modules/node/config/install/views.view.archive.yml b/core/modules/node/config/install/views.view.archive.yml
index d9b5921..dc789a5 100644
--- a/core/modules/node/config/install/views.view.archive.yml
+++ b/core/modules/node/config/install/views.view.archive.yml
@@ -16,7 +16,7 @@ display:
           query_comment: false
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_tags: {  }
         provider: views
       title: 'Monthly archive'
diff --git a/core/modules/node/config/install/views.view.content_recent.yml b/core/modules/node/config/install/views.view.content_recent.yml
index 1b78d3d..2b09e07 100644
--- a/core/modules/node/config/install/views.view.content_recent.yml
+++ b/core/modules/node/config/install/views.view.content_recent.yml
@@ -24,7 +24,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/node/config/install/views.view.frontpage.yml b/core/modules/node/config/install/views.view.frontpage.yml
index 0dc004c..a84f40b 100644
--- a/core/modules/node/config/install/views.view.frontpage.yml
+++ b/core/modules/node/config/install/views.view.frontpage.yml
@@ -137,7 +137,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/node/config/install/views.view.glossary.yml b/core/modules/node/config/install/views.view.glossary.yml
index 9ddc7b5..5667615 100644
--- a/core/modules/node/config/install/views.view.glossary.yml
+++ b/core/modules/node/config/install/views.view.glossary.yml
@@ -16,7 +16,7 @@ display:
           query_comment: false
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_tags: {  }
         provider: views
       use_ajax: true
diff --git a/core/modules/node/src/Plugin/Search/NodeSearch.php b/core/modules/node/src/Plugin/Search/NodeSearch.php
index 1bcd79b..e300449 100644
--- a/core/modules/node/src/Plugin/Search/NodeSearch.php
+++ b/core/modules/node/src/Plugin/Search/NodeSearch.php
@@ -181,7 +181,7 @@ public function execute() {
 
     // Build matching conditions.
     $query = $this->database
-      ->select('search_index', 'i', array('target' => 'slave'))
+      ->select('search_index', 'i', array('target' => 'secondary'))
       ->extend('Drupal\search\SearchQuery')
       ->extend('Drupal\Core\Database\Query\PagerSelectExtender');
     $query->join('node_field_data', 'n', 'n.nid = i.sid');
@@ -324,7 +324,7 @@ public function updateIndex() {
     // per cron run.
     $limit = (int) $this->searchSettings->get('index.cron_limit');
 
-    $result = $this->database->queryRange("SELECT n.nid, MAX(sd.reindex) FROM {node} n LEFT JOIN {search_dataset} sd ON sd.sid = n.nid AND sd.type = :type WHERE sd.sid IS NULL OR sd.reindex <> 0 GROUP BY n.nid ORDER BY MAX(sd.reindex) is null DESC, MAX(sd.reindex) ASC, n.nid ASC", 0, $limit, array(':type' => $this->getPluginId()), array('target' => 'slave'));
+    $result = $this->database->queryRange("SELECT n.nid, MAX(sd.reindex) FROM {node} n LEFT JOIN {search_dataset} sd ON sd.sid = n.nid AND sd.type = :type WHERE sd.sid IS NULL OR sd.reindex <> 0 GROUP BY n.nid ORDER BY MAX(sd.reindex) is null DESC, MAX(sd.reindex) ASC, n.nid ASC", 0, $limit, array(':type' => $this->getPluginId()), array('target' => 'secondary'));
     $nids = $result->fetchCol();
     if (!$nids) {
       return;
diff --git a/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_contextual_links.yml b/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_contextual_links.yml
index aa0b719..125bef6 100644
--- a/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_contextual_links.yml
+++ b/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_contextual_links.yml
@@ -39,7 +39,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: ''
           query_tags: {  }
       row:
diff --git a/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_node_view.yml b/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_node_view.yml
index ed25f0c..071fb29 100644
--- a/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_node_view.yml
+++ b/core/modules/node/tests/modules/node_test_views/test_views/views.view.test_node_view.yml
@@ -29,7 +29,7 @@ display:
         options:
           disable_sql_rewrite: '0'
           distinct: '0'
-          slave: '0'
+          secondary: '0'
           query_comment: ''
           query_tags: {  }
       exposed_form:
diff --git a/core/modules/search/search.module b/core/modules/search/search.module
index 1af2be8..eafcd41 100644
--- a/core/modules/search/search.module
+++ b/core/modules/search/search.module
@@ -221,7 +221,7 @@ function search_update_totals() {
   // 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", array(':word' => $word), array('target' => 'slave'))->fetchField();
+    $total = db_query("SELECT SUM(score) FROM {search_index} WHERE word = :word", array(':word' => $word), array('target' => 'secondary'))->fetchField();
     // Apply Zipf's law to equalize the probability distribution.
     $total = log10(1 + 1/(max(1, $total)));
     db_merge('search_total')
@@ -232,7 +232,7 @@ function search_update_totals() {
   // Find words that were deleted from search_index, but are still in
   // search_total. We use a LEFT JOIN between the two tables and keep only the
   // rows which fail to join.
-  $result = db_query("SELECT t.word AS realword, i.word FROM {search_total} t LEFT JOIN {search_index} i ON t.word = i.word WHERE i.word IS NULL", array(), array('target' => 'slave'));
+  $result = db_query("SELECT t.word AS realword, i.word FROM {search_total} t LEFT JOIN {search_index} i ON t.word = i.word WHERE i.word IS NULL", array(), array('target' => 'secondary'));
   $or = db_or();
   foreach ($result as $word) {
     $or->condition('word', $word->realword);
diff --git a/core/modules/search/src/Plugin/views/argument/Search.php b/core/modules/search/src/Plugin/views/argument/Search.php
index d2e0ee7..0611004 100644
--- a/core/modules/search/src/Plugin/views/argument/Search.php
+++ b/core/modules/search/src/Plugin/views/argument/Search.php
@@ -52,7 +52,7 @@ public function init(ViewExecutable $view, DisplayPluginBase $display, array &$o
    */
   protected function queryParseSearchExpression($input) {
     if (!isset($this->searchQuery)) {
-      $this->searchQuery = db_select('search_index', 'i', array('target' => 'slave'))->extend('Drupal\search\ViewsSearchQuery');
+      $this->searchQuery = db_select('search_index', 'i', array('target' => 'secondary'))->extend('Drupal\search\ViewsSearchQuery');
       $this->searchQuery->searchExpression($input, $this->searchType);
       $this->searchQuery->publicParseSearchExpression();
     }
diff --git a/core/modules/search/src/Plugin/views/filter/Search.php b/core/modules/search/src/Plugin/views/filter/Search.php
index 4db2dc2..9f8f0e0 100644
--- a/core/modules/search/src/Plugin/views/filter/Search.php
+++ b/core/modules/search/src/Plugin/views/filter/Search.php
@@ -121,7 +121,7 @@ public function validateExposed(&$form, &$form_state) {
   protected function queryParseSearchExpression($input) {
     if (!isset($this->searchQuery)) {
       $this->parsed = TRUE;
-      $this->searchQuery = db_select('search_index', 'i', array('target' => 'slave'))->extend('Drupal\search\ViewsSearchQuery');
+      $this->searchQuery = db_select('search_index', 'i', array('target' => 'secondary'))->extend('Drupal\search\ViewsSearchQuery');
       $this->searchQuery->searchExpression($input, $this->searchType);
       $this->searchQuery->publicParseSearchExpression();
     }
diff --git a/core/modules/search/src/SearchQuery.php b/core/modules/search/src/SearchQuery.php
index 3e7d638..02f02b8 100644
--- a/core/modules/search/src/SearchQuery.php
+++ b/core/modules/search/src/SearchQuery.php
@@ -600,7 +600,7 @@ public function countQuery() {
     $expressions = array();
 
     // Add sid as the only field and count them as a subquery.
-    $count = db_select($inner->fields('i', array('sid')), NULL, array('target' => 'slave'));
+    $count = db_select($inner->fields('i', array('sid')), NULL, array('target' => 'secondary'));
 
     // Add the COUNT() expression.
     $count->addExpression('COUNT(*)');
diff --git a/core/modules/statistics/statistics.module b/core/modules/statistics/statistics.module
index e5828c3..eddaa97 100644
--- a/core/modules/statistics/statistics.module
+++ b/core/modules/statistics/statistics.module
@@ -155,7 +155,7 @@ function statistics_get($nid) {
 
   if ($nid > 0) {
     // Retrieve an array with both totalcount and daycount.
-    return db_query('SELECT totalcount, daycount, timestamp FROM {node_counter} WHERE nid = :nid', array(':nid' => $nid), array('target' => 'slave'))->fetchAssoc();
+    return db_query('SELECT totalcount, daycount, timestamp FROM {node_counter} WHERE nid = :nid', array(':nid' => $nid), array('target' => 'secondary'))->fetchAssoc();
   }
 }
 
diff --git a/core/modules/system/src/Tests/Database/ConnectionTest.php b/core/modules/system/src/Tests/Database/ConnectionTest.php
index c20d83d..e53d0fd 100644
--- a/core/modules/system/src/Tests/Database/ConnectionTest.php
+++ b/core/modules/system/src/Tests/Database/ConnectionTest.php
@@ -26,22 +26,22 @@ public static function getInfo() {
    * Tests that connections return appropriate connection objects.
    */
   function testConnectionRouting() {
-    // Clone the master credentials to a slave connection.
+    // Clone the primary credentials to a secondary connection.
     // Note this will result in two independent connection objects that happen
     // to point to the same place.
     $connection_info = Database::getConnectionInfo('default');
-    Database::addConnectionInfo('default', 'slave', $connection_info['default']);
+    Database::addConnectionInfo('default', 'secondary', $connection_info['default']);
 
     $db1 = Database::getConnection('default', 'default');
-    $db2 = Database::getConnection('slave', 'default');
+    $db2 = Database::getConnection('secondary', 'default');
 
     $this->assertNotNull($db1, 'default connection is a real connection object.');
-    $this->assertNotNull($db2, 'slave connection is a real connection object.');
+    $this->assertNotNull($db2, 'secondary connection is a real connection object.');
     $this->assertNotIdentical($db1, $db2, 'Each target refers to a different connection.');
 
     // Try to open those targets another time, that should return the same objects.
     $db1b = Database::getConnection('default', 'default');
-    $db2b = Database::getConnection('slave', 'default');
+    $db2b = Database::getConnection('secondary', 'default');
     $this->assertIdentical($db1, $db1b, 'A second call to getConnection() returns the same object.');
     $this->assertIdentical($db2, $db2b, 'A second call to getConnection() returns the same object.');
 
@@ -60,16 +60,16 @@ function testConnectionRouting() {
    * Tests that connections return appropriate connection objects.
    */
   function testConnectionRoutingOverride() {
-    // Clone the master credentials to a slave connection.
+    // Clone the primary credentials to a secondary connection.
     // Note this will result in two independent connection objects that happen
     // to point to the same place.
     $connection_info = Database::getConnectionInfo('default');
-    Database::addConnectionInfo('default', 'slave', $connection_info['default']);
+    Database::addConnectionInfo('default', 'secondary', $connection_info['default']);
 
-    Database::ignoreTarget('default', 'slave');
+    Database::ignoreTarget('default', 'secondary');
 
     $db1 = Database::getConnection('default', 'default');
-    $db2 = Database::getConnection('slave', 'default');
+    $db2 = Database::getConnection('secondary', 'default');
 
     $this->assertIdentical($db1, $db2, 'Both targets refer to the same connection.');
   }
@@ -104,14 +104,14 @@ function testConnectionOptions() {
     $this->assertEqual($connection_info['default']['driver'], $connectionOptions['driver'], 'The default connection info driver matches the current connection options driver.');
     $this->assertEqual($connection_info['default']['database'], $connectionOptions['database'], 'The default connection info database matches the current connection options database.');
 
-    // Set up identical slave and confirm connection options are identical.
-    Database::addConnectionInfo('default', 'slave', $connection_info['default']);
-    $db2 = Database::getConnection('slave', 'default');
+    // Set up identical secondary and confirm connection options are identical.
+    Database::addConnectionInfo('default', 'secondary', $connection_info['default']);
+    $db2 = Database::getConnection('secondary', 'default');
     $connectionOptions2 = $db2->getConnectionOptions();
 
     // Get a fresh copy of the default connection options.
     $connectionOptions = $db->getConnectionOptions();
-    $this->assertIdentical($connectionOptions, $connectionOptions2, 'The default and slave connection options are identical.');
+    $this->assertIdentical($connectionOptions, $connectionOptions2, 'The default and secondary connection options are identical.');
 
     // Set up a new connection with different connection info.
     $test = $connection_info['default'];
diff --git a/core/modules/system/src/Tests/Database/LoggingTest.php b/core/modules/system/src/Tests/Database/LoggingTest.php
index 134e193..2defb85 100644
--- a/core/modules/system/src/Tests/Database/LoggingTest.php
+++ b/core/modules/system/src/Tests/Database/LoggingTest.php
@@ -66,22 +66,22 @@ function testEnableMultiLogging() {
    * Tests logging queries against multiple targets on the same connection.
    */
   function testEnableTargetLogging() {
-    // Clone the master credentials to a slave connection and to another fake
+    // Clone the primary credentials to a secondary connection and to another fake
     // connection.
     $connection_info = Database::getConnectionInfo('default');
-    Database::addConnectionInfo('default', 'slave', $connection_info['default']);
+    Database::addConnectionInfo('default', 'secondary', $connection_info['default']);
 
     Database::startLog('testing1');
 
     db_query('SELECT name FROM {test} WHERE age > :age', array(':age' => 25))->fetchCol();
 
-    db_query('SELECT age FROM {test} WHERE name = :name', array(':name' => 'Ringo'), array('target' => 'slave'));//->fetchCol();
+    db_query('SELECT age FROM {test} WHERE name = :name', array(':name' => 'Ringo'), array('target' => 'secondary'));//->fetchCol();
 
     $queries1 = Database::getLog('testing1');
 
     $this->assertEqual(count($queries1), 2, 'Recorded queries from all targets.');
     $this->assertEqual($queries1[0]['target'], 'default', 'First query used default target.');
-    $this->assertEqual($queries1[1]['target'], 'slave', 'Second query used slave target.');
+    $this->assertEqual($queries1[1]['target'], 'secondary', 'Second query used secondary target.');
   }
 
   /**
@@ -98,7 +98,7 @@ function testEnableTargetLoggingNoTarget() {
 
     // We use "fake" here as a target because any non-existent target will do.
     // However, because all of the tests in this class share a single page
-    // request there is likely to be a target of "slave" from one of the other
+    // request there is likely to be a target of "secondary" from one of the other
     // unit tests, so we use a target here that we know with absolute certainty
     // does not exist.
     db_query('SELECT age FROM {test} WHERE name = :name', array(':name' => 'Ringo'), array('target' => 'fake'))->fetchCol();
@@ -114,7 +114,7 @@ function testEnableTargetLoggingNoTarget() {
    * Tests that we can log queries separately on different connections.
    */
   function testEnableMultiConnectionLogging() {
-    // Clone the master credentials to a fake connection.
+    // Clone the primary credentials to a fake connection.
     // That both connections point to the same physical database is irrelevant.
     $connection_info = Database::getConnectionInfo('default');
     Database::addConnectionInfo('test2', 'default', $connection_info['default']);
@@ -126,7 +126,7 @@ function testEnableMultiConnectionLogging() {
 
     $old_key = db_set_active('test2');
 
-    db_query('SELECT age FROM {test} WHERE name = :name', array(':name' => 'Ringo'), array('target' => 'slave'))->fetchCol();
+    db_query('SELECT age FROM {test} WHERE name = :name', array(':name' => 'Ringo'), array('target' => 'secondary'))->fetchCol();
 
     db_set_active($old_key);
 
diff --git a/core/modules/system/src/Tests/Database/SelectComplexTest.php b/core/modules/system/src/Tests/Database/SelectComplexTest.php
index 7e7d24d..7dd0f89 100644
--- a/core/modules/system/src/Tests/Database/SelectComplexTest.php
+++ b/core/modules/system/src/Tests/Database/SelectComplexTest.php
@@ -337,7 +337,7 @@ function testJoinSubquery() {
       'mail' => $this->randomName() . '@example.com',
     ));
 
-    $query = db_select('test_task', 'tt', array('target' => 'slave'));
+    $query = db_select('test_task', 'tt', array('target' => 'secondary'));
     $query->addExpression('tt.pid + 1', 'abc');
     $query->condition('priority', 1, '>');
     $query->condition('priority', 100, '<');
diff --git a/core/modules/system/src/Tests/System/IgnoreSecondarySubscriberTest.php b/core/modules/system/src/Tests/System/IgnoreSecondarySubscriberTest.php
new file mode 100644
index 0000000..1cc8d84
--- /dev/null
+++ b/core/modules/system/src/Tests/System/IgnoreSecondarySubscriberTest.php
@@ -0,0 +1,51 @@
+<?php
+
+/**
+ * Contains \Drupal\system\Tests\System\IgnoreSecondarySubscriberTest.
+ */
+
+namespace Drupal\system\Tests\System;
+
+use Drupal\Core\Database\Database;
+use Drupal\Core\EventSubscriber\SecondaryDatabaseIgnoreSubscriber;
+use Drupal\Core\DrupalKernel;
+use Drupal\simpletest\UnitTestBase;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+
+/**
+ * Tests the event subscriber that disables the secondary database.
+ */
+class IgnoreSecondarySubscriberTest extends UnitTestBase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Secondary database ignoring event listener',
+      'description' => 'Tests that SecondaryDatabaseIgnoreSubscriber functions correctly.',
+      'group' => 'System',
+    );
+  }
+
+  /**
+   * Tests \Drupal\Core\EventSubscriber\SecondaryDatabaseIgnoreSubscriber::checkSecondaryServer().
+   */
+  function testSystemInitIgnoresSecondaries() {
+    // Clone the master credentials to a secondary connection.
+    // Note this will result in two independent connection objects that happen
+    // to point to the same place.
+    $connection_info = Database::getConnectionInfo('default');
+    Database::addConnectionInfo('default', 'secondary', $connection_info['default']);
+
+    db_ignore_secondary();
+    $kernel = new DrupalKernel('testing', drupal_classloader(), FALSE);
+    $event = new GetResponseEvent($kernel, Request::create('http://example.com'), HttpKernelInterface::MASTER_REQUEST);
+    $subscriber = new SecondaryDatabaseIgnoreSubscriber();
+    $subscriber->checkSecondaryServer($event);
+
+    $db1 = Database::getConnection('default', 'default');
+    $db2 = Database::getConnection('secondary', 'default');
+
+    $this->assertIdentical($db1, $db2, 'System Init ignores secondaries when requested.');
+  }
+}
diff --git a/core/modules/system/src/Tests/System/IgnoreSlaveSubscriberTest.php b/core/modules/system/src/Tests/System/IgnoreSlaveSubscriberTest.php
deleted file mode 100644
index da65377..0000000
--- a/core/modules/system/src/Tests/System/IgnoreSlaveSubscriberTest.php
+++ /dev/null
@@ -1,51 +0,0 @@
-<?php
-
-/**
- * Contains \Drupal\system\Tests\System\IgnoreSlaveSubscriberTest.
- */
-
-namespace Drupal\system\Tests\System;
-
-use Drupal\Core\Database\Database;
-use Drupal\Core\EventSubscriber\SlaveDatabaseIgnoreSubscriber;
-use Drupal\Core\DrupalKernel;
-use Drupal\simpletest\UnitTestBase;
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpKernel\HttpKernelInterface;
-use Symfony\Component\HttpKernel\Event\GetResponseEvent;
-
-/**
- * Tests the event subscriber that disables the slave database.
- */
-class IgnoreSlaveSubscriberTest extends UnitTestBase {
-
-  public static function getInfo() {
-    return array(
-      'name' => 'Slave database ignoring event listener',
-      'description' => 'Tests that SlaveDatabaseIgnoreSubscriber functions correctly.',
-      'group' => 'System',
-    );
-  }
-
-  /**
-   * Tests \Drupal\Core\EventSubscriber\SlaveDatabaseIgnoreSubscriber::checkSlaveServer().
-   */
-  function testSystemInitIgnoresSlaves() {
-    // Clone the master credentials to a slave connection.
-    // Note this will result in two independent connection objects that happen
-    // to point to the same place.
-    $connection_info = Database::getConnectionInfo('default');
-    Database::addConnectionInfo('default', 'slave', $connection_info['default']);
-
-    db_ignore_slave();
-    $kernel = new DrupalKernel('testing', drupal_classloader(), FALSE);
-    $event = new GetResponseEvent($kernel, Request::create('http://example.com'), HttpKernelInterface::MASTER_REQUEST);
-    $subscriber = new SlaveDatabaseIgnoreSubscriber();
-    $subscriber->checkSlaveServer($event);
-
-    $db1 = Database::getConnection('default', 'default');
-    $db2 = Database::getConnection('slave', 'default');
-
-    $this->assertIdentical($db1, $db2, 'System Init ignores slaves when requested.');
-  }
-}
diff --git a/core/modules/taxonomy/config/install/views.view.taxonomy_term.yml b/core/modules/taxonomy/config/install/views.view.taxonomy_term.yml
index c39264f..098c55f 100644
--- a/core/modules/taxonomy/config/install/views.view.taxonomy_term.yml
+++ b/core/modules/taxonomy/config/install/views.view.taxonomy_term.yml
@@ -16,7 +16,7 @@ display:
           query_comment: false
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_tags: {  }
         provider: views
       access:
diff --git a/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_filter_taxonomy_index_tid.yml b/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_filter_taxonomy_index_tid.yml
index 716ccdc..f6abc37 100644
--- a/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_filter_taxonomy_index_tid.yml
+++ b/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_filter_taxonomy_index_tid.yml
@@ -22,7 +22,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: ''
           query_tags: {  }
       exposed_form:
diff --git a/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_taxonomy_parent.yml b/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_taxonomy_parent.yml
index 129c719..09fd592 100644
--- a/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_taxonomy_parent.yml
+++ b/core/modules/taxonomy/tests/modules/taxonomy_test_views/test_views/views.view.test_taxonomy_parent.yml
@@ -25,7 +25,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/tracker/tracker.module b/core/modules/tracker/tracker.module
index 73d2954..08420d4 100644
--- a/core/modules/tracker/tracker.module
+++ b/core/modules/tracker/tracker.module
@@ -46,7 +46,7 @@ function tracker_cron() {
     $last_nid = FALSE;
     // @todo This should be actually filtering on the desired language and just
     //   fall back to the default language.
-    $result = db_query_range('SELECT nid, uid, status FROM {node_field_data} WHERE nid <= :max_nid AND default_langcode = 1 ORDER BY nid DESC', 0, $batch_size, array(':max_nid' => $max_nid), array('target' => 'slave'));
+    $result = db_query_range('SELECT nid, uid, status FROM {node_field_data} WHERE nid <= :max_nid AND default_langcode = 1 ORDER BY nid DESC', 0, $batch_size, array(':max_nid' => $max_nid), array('target' => 'secondary'));
 
     $count = 0;
 
@@ -81,7 +81,7 @@ function tracker_cron() {
         ))
         ->execute();
 
-      $query = db_select('comment', 'c', array('target' => 'slave'));
+      $query = db_select('comment', 'c', array('target' => 'secondary'));
       // Force PostgreSQL to do an implicit cast by adding 0.
       $query->addExpression('0 + :changed', 'changed', array(':changed' => $changed));
       $query->addField('c', 'status', 'published');
@@ -290,11 +290,11 @@ function _tracker_add($nid, $uid, $changed) {
 function _tracker_calculate_changed($nid) {
   // @todo This should be actually filtering on the desired language and just
   //   fall back to the default language.
-  $changed = db_query('SELECT changed FROM {node_field_data} WHERE nid = :nid AND default_langcode = 1 ORDER BY changed DESC', array(':nid' => $nid), array('target' => 'slave'))->fetchField();
+  $changed = db_query('SELECT changed FROM {node_field_data} WHERE nid = :nid AND default_langcode = 1 ORDER BY changed DESC', array(':nid' => $nid), array('target' => 'secondary'))->fetchField();
   $latest_comment = db_query_range("SELECT cid, changed FROM {comment} WHERE entity_type = 'node' AND entity_id = :nid AND status = :status ORDER BY changed DESC", 0, 1, array(
     ':nid' => $nid,
     ':status' => CommentInterface::PUBLISHED,
-  ), array('target' => 'slave'))->fetchObject();
+  ), array('target' => 'secondary'))->fetchObject();
   if ($latest_comment && $latest_comment->changed > $changed) {
     $changed = $latest_comment->changed;
   }
diff --git a/core/modules/tracker/tracker.pages.inc b/core/modules/tracker/tracker.pages.inc
index 30c7915..8dca90f 100644
--- a/core/modules/tracker/tracker.pages.inc
+++ b/core/modules/tracker/tracker.pages.inc
@@ -25,7 +25,7 @@ function tracker_page($account = NULL) {
       ->condition('t.uid', $account->id());
   }
   else {
-    $query = db_select('tracker_node', 't', array('target' => 'slave'))
+    $query = db_select('tracker_node', 't', array('target' => 'secondary'))
       ->extend('Drupal\Core\Database\Query\PagerSelectExtender')
       ->addMetaData('base_table', 'tracker_node');
   }
@@ -61,7 +61,7 @@ function tracker_page($account = NULL) {
     GROUP BY n.nid
     ORDER BY n.changed DESC", array(
       ':nids' => array_keys($nodes)
-    ), array('target' => 'slave'))->fetchAllKeyed();
+    ), array('target' => 'secondary'))->fetchAllKeyed();
     foreach ($result as $nid => $comment_count) {
       $nodes[$nid]->last_activity = $tracker_data[$nid]->changed;
       $nodes[$nid]->comment_count = $comment_count;
diff --git a/core/modules/user/config/install/views.view.user_admin_people.yml b/core/modules/user/config/install/views.view.user_admin_people.yml
index 6ab676d..c6cc75a 100644
--- a/core/modules/user/config/install/views.view.user_admin_people.yml
+++ b/core/modules/user/config/install/views.view.user_admin_people.yml
@@ -23,7 +23,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/user/config/install/views.view.who_s_new.yml b/core/modules/user/config/install/views.view.who_s_new.yml
index 45566ae..4961326 100644
--- a/core/modules/user/config/install/views.view.who_s_new.yml
+++ b/core/modules/user/config/install/views.view.who_s_new.yml
@@ -24,7 +24,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/user/config/install/views.view.who_s_online.yml b/core/modules/user/config/install/views.view.who_s_online.yml
index 911f40f..5803425 100644
--- a/core/modules/user/config/install/views.view.who_s_online.yml
+++ b/core/modules/user/config/install/views.view.who_s_online.yml
@@ -24,7 +24,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
         provider: views
diff --git a/core/modules/views/config/schema/views.data_types.schema.yml b/core/modules/views/config/schema/views.data_types.schema.yml
index ae143bb..787d770 100644
--- a/core/modules/views/config/schema/views.data_types.schema.yml
+++ b/core/modules/views/config/schema/views.data_types.schema.yml
@@ -832,9 +832,9 @@ views_query:
     distinct:
       type: boolean
       label: 'Distinct'
-    slave:
+    secondary:
       type: boolean
-      label: 'Use Slave Server'
+      label: 'Use Secondary Server'
     query_tags:
       type: sequence
       label: 'Query Tags'
diff --git a/core/modules/views/src/Plugin/views/query/Sql.php b/core/modules/views/src/Plugin/views/query/Sql.php
index 5b51afd..35d9c91 100644
--- a/core/modules/views/src/Plugin/views/query/Sql.php
+++ b/core/modules/views/src/Plugin/views/query/Sql.php
@@ -181,7 +181,7 @@ protected function defineOptions() {
       'default' => FALSE,
       'bool' => TRUE,
     );
-    $options['slave'] = array(
+    $options['secondary'] = array(
       'default' => FALSE,
       'bool' => TRUE,
     );
@@ -214,11 +214,11 @@ public function buildOptionsForm(&$form, &$form_state) {
       '#description' => t('This will make the view display only distinct items. If there are multiple identical items, each will be displayed only once. You can use this to try and remove duplicates from a view, though it does not always work. Note that this can slow queries down, so use it with caution.'),
       '#default_value' => !empty($this->options['distinct']),
     );
-    $form['slave'] = array(
+    $form['secondary'] = array(
       '#type' => 'checkbox',
-      '#title' => t('Use Slave Server'),
-      '#description' => t('This will make the query attempt to connect to a slave server if available.  If no slave server is defined or available, it will fall back to the default server.'),
-      '#default_value' => !empty($this->options['slave']),
+      '#title' => t('Use Secondary Server'),
+      '#description' => t('This will make the query attempt to connect to a secondary server if available.  If no secondary server is defined or available, it will fall back to the default server.'),
+      '#default_value' => !empty($this->options['secondary']),
     );
     $form['query_comment'] = array(
       '#type' => 'textfield',
@@ -1204,9 +1204,9 @@ public function query($get_count = FALSE) {
       $key = $this->view->base_database;
     }
 
-    // Set the slave target if the slave option is set
-    if (!empty($this->options['slave'])) {
-      $target = 'slave';
+    // Set the secondary target if the secondary option is set
+    if (!empty($this->options['secondary'])) {
+      $target = 'secondary';
     }
 
     // Go ahead and build the query.
diff --git a/core/modules/views/tests/modules/views_test_config/test_views/views.view.test_search.yml b/core/modules/views/tests/modules/views_test_config/test_views/views.view.test_search.yml
index 57d96a8..19dc91d 100644
--- a/core/modules/views/tests/modules/views_test_config/test_views/views.view.test_search.yml
+++ b/core/modules/views/tests/modules/views_test_config/test_views/views.view.test_search.yml
@@ -87,7 +87,7 @@ display:
         options:
           disable_sql_rewrite: false
           distinct: false
-          slave: false
+          secondary: false
           query_comment: false
           query_tags: {  }
       exposed_form:
diff --git a/sites/default/default.settings.php b/sites/default/default.settings.php
index c8d135a..8a2215f 100644
--- a/sites/default/default.settings.php
+++ b/sites/default/default.settings.php
@@ -98,22 +98,22 @@
  * For each database, you may optionally specify multiple "target" databases.
  * A target database allows Drupal to try to send certain queries to a
  * different database if it can but fall back to the default connection if not.
- * That is useful for master/slave replication, as Drupal may try to connect
- * to a slave server when appropriate and if one is not available will simply
- * fall back to the single master server.
+ * That is useful for primary/secondary replication, as Drupal may try to connect
+ * to a secondary server when appropriate and if one is not available will simply
+ * fall back to the single primary server.
  *
  * The general format for the $databases array is as follows:
  * @code
  * $databases['default']['default'] = $info_array;
- * $databases['default']['slave'][] = $info_array;
- * $databases['default']['slave'][] = $info_array;
+ * $databases['default']['secondary'][] = $info_array;
+ * $databases['default']['secondary'][] = $info_array;
  * $databases['extra']['default'] = $info_array;
  * @endcode
  *
  * In the above example, $info_array is an array of settings described above.
- * The first line sets a "default" database that has one master database
+ * The first line sets a "default" database that has one primary database
  * (the second level default).  The second and third lines create an array
- * of potential slave databases.  Drupal will select one at random for a given
+ * of potential secondary databases.  Drupal will select one at random for a given
  * request as needed.  The fourth line creates a new database with a name of
  * "extra".
  *