diff --git a/core/lib/Drupal/Core/Database/Connection.php b/core/lib/Drupal/Core/Database/Connection.php
index b088f66..a56bcf6 100644
--- a/core/lib/Drupal/Core/Database/Connection.php
+++ b/core/lib/Drupal/Core/Database/Connection.php
@@ -139,11 +139,11 @@
   protected $prefixReplace = array();
 
   /**
-   * List of un-prefixed table names, keyed by fully qualified table names.
+   * List of un-prefixed table names, keyed by prefixed table names.
    *
    * @var array
    */
-  protected $prefixedTablesMap = [];
+  protected $unprefixedTablesMap = [];
 
   /**
    * Constructs a Connection object.
@@ -302,7 +302,7 @@ protected function setPrefix($prefix) {
     // Set up a map of prefixed => un-prefixed tables.
     foreach ($this->prefixes as $table_name => $prefix) {
       if ($table_name !== 'default') {
-        $this->prefixedTablesMap[$prefix . $table_name] = $table_name;
+        $this->unprefixedTablesMap[$prefix . $table_name] = $table_name;
       }
     }
   }
@@ -350,8 +350,8 @@ public function tablePrefix($table = 'default') {
    *   An array of un-prefixed table names, keyed by their fully qualified table
    *   names (i.e. prefix + table_name).
    */
-  public function getPrefixedTablesMap() {
-    return $this->prefixedTablesMap;
+  public function getUnprefixedTablesMap() {
+    return $this->unprefixedTablesMap;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Database/Schema.php b/core/lib/Drupal/Core/Database/Schema.php
index cf8206f..8f2c758 100644
--- a/core/lib/Drupal/Core/Database/Schema.php
+++ b/core/lib/Drupal/Core/Database/Schema.php
@@ -192,7 +192,7 @@ public function findTables($table_expression) {
     $condition = $this->buildTableNameCondition('%', 'LIKE');
     $condition->compile($this->connection, $this);
 
-    $individually_prefixed_tables = $this->connection->getPrefixedTablesMap();
+    $individually_prefixed_tables = $this->connection->getUnprefixedTablesMap();
     $default_prefix_length = strlen($this->connection->tablePrefix());
     $tables = [];
     // Normally, we would heartily discourage the use of string
@@ -200,7 +200,8 @@ public function findTables($table_expression) {
     // couldn't use db_select() here because it would prefix
     // information_schema.tables and the query would fail.
     // Don't use {} around information_schema.tables table.
-    foreach ($this->connection->query("SELECT table_name FROM information_schema.tables WHERE " . (string) $condition, $condition->arguments()) as $table) {
+    $results = $this->connection->query("SELECT table_name FROM information_schema.tables WHERE " . (string) $condition, $condition->arguments());
+    foreach ($results as $table) {
       // Take into account tables that have an individual prefix.
       if (isset($individually_prefixed_tables[$table->table_name])) {
         $prefix_length = strlen($this->connection->tablePrefix($individually_prefixed_tables[$table->table_name]));