diff --git a/core/lib/Drupal/Core/Database/Connection.php b/core/lib/Drupal/Core/Database/Connection.php
index 3b194f6..6e87303 100644
--- a/core/lib/Drupal/Core/Database/Connection.php
+++ b/core/lib/Drupal/Core/Database/Connection.php
@@ -544,6 +544,7 @@ public function query($query, array $args = array(), $options = array()) {
         case Database::RETURN_STATEMENT:
           return $stmt;
         case Database::RETURN_AFFECTED:
+          $stmt->allowRowCount = TRUE;
           return $stmt->rowCount();
         case Database::RETURN_INSERT_ID:
           return $this->connection->lastInsertId();
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
index 68e9c98..9b9cf97 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
@@ -130,6 +130,7 @@ public function query($query, array $args = array(), $options = array()) {
 
       switch ($options['return']) {
         case Database::RETURN_STATEMENT:
+          $stmt->allowRowCount = FALSE;
           return $stmt;
         case Database::RETURN_AFFECTED:
           return $stmt->rowCount();
diff --git a/core/lib/Drupal/Core/Database/RowCountException.php b/core/lib/Drupal/Core/Database/RowCountException.php
new file mode 100644
index 0000000..6f4a34a
--- /dev/null
+++ b/core/lib/Drupal/Core/Database/RowCountException.php
@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Database\RowCountException
+ */
+
+namespace Drupal\Core\Database;
+
+/**
+ * Exception thrown if a SELECT query trying to execute rowCount() on result.
+ */
+class RowCountException extends \RuntimeException implements DatabaseException { }
diff --git a/core/lib/Drupal/Core/Database/Statement.php b/core/lib/Drupal/Core/Database/Statement.php
index e7463b3..ca70c4c 100644
--- a/core/lib/Drupal/Core/Database/Statement.php
+++ b/core/lib/Drupal/Core/Database/Statement.php
@@ -29,6 +29,13 @@ class Statement extends \PDOStatement implements StatementInterface {
    */
   public $dbh;
 
+  /**
+   * Is rowCount() execution allowed.
+   *
+   * @var bool
+   */
+  public $allowRowCount = FALSE;
+
   protected function __construct(Connection $dbh) {
     $this->dbh = $dbh;
     $this->setFetchMode(\PDO::FETCH_OBJ);
@@ -106,4 +113,18 @@ public function fetchAssoc() {
     // Call \PDOStatement::fetch to fetch the row.
     return $this->fetch(\PDO::FETCH_ASSOC);
   }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function rowCount() {
+    // SELECT query should not use the method.
+    if ($this->allowRowCount) {
+      return parent::rowCount();
+    }
+    else {
+      throw new RowCountException();
+    }
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Database/StatementEmpty.php b/core/lib/Drupal/Core/Database/StatementEmpty.php
index 7a09add..e6cd08d 100644
--- a/core/lib/Drupal/Core/Database/StatementEmpty.php
+++ b/core/lib/Drupal/Core/Database/StatementEmpty.php
@@ -21,6 +21,13 @@
  */
 class StatementEmpty implements \Iterator, StatementInterface {
 
+  /**
+   * Is rowCount() execution allowed.
+   *
+   * @var bool
+   */
+  public $allowRowCount = FALSE;
+
   public function execute($args = array(), $options = array()) {
     return FALSE;
   }
@@ -30,7 +37,10 @@ public function getQueryString() {
   }
 
   public function rowCount() {
-    return 0;
+    if ($this->allowRowCount) {
+      return 0;
+    }
+    throw new RowCountException();
   }
 
   public function setFetchMode($mode, $a1 = NULL, $a2 = array()) {
diff --git a/core/lib/Drupal/Core/Database/StatementInterface.php b/core/lib/Drupal/Core/Database/StatementInterface.php
index 18c2923..e93e916 100644
--- a/core/lib/Drupal/Core/Database/StatementInterface.php
+++ b/core/lib/Drupal/Core/Database/StatementInterface.php
@@ -74,7 +74,10 @@ public function getQueryString();
    *
    * @return
    *   The number of rows affected by the last DELETE, INSERT, or UPDATE
-   *   statement executed.
+   *   statement executed or throws \Drupal\Core\Database\RowCountException
+   *   if the last executed statement was SELECT.
+   *
+   * @throws \Drupal\Core\Database\RowCountException
    */
   public function rowCount();
 
diff --git a/core/lib/Drupal/Core/Database/StatementPrefetch.php b/core/lib/Drupal/Core/Database/StatementPrefetch.php
index bedf12e..c32d94a 100644
--- a/core/lib/Drupal/Core/Database/StatementPrefetch.php
+++ b/core/lib/Drupal/Core/Database/StatementPrefetch.php
@@ -128,6 +128,13 @@ class StatementPrefetch implements \Iterator, StatementInterface {
     'column' => 0,
   );
 
+  /**
+   * Is rowCount() execution allowed.
+   *
+   * @var bool
+   */
+  public $allowRowCount = FALSE;
+
   public function __construct(\PDO $dbh, Connection $connection, $query, array $driver_options = array()) {
     $this->dbh = $dbh;
     $this->connection = $connection;
@@ -174,9 +181,11 @@ public function execute($args = array(), $options = array()) {
       $this->throwPDOException();
     }
 
+    if ($options['return'] == Database::RETURN_AFFECTED) {
+      $this->rowCount = $statement->rowCount();
+    }
     // Fetch all the data from the reply, in order to release any lock
     // as soon as possible.
-    $this->rowCount = $statement->rowCount();
     $this->data = $statement->fetchAll(\PDO::FETCH_ASSOC);
     // Destroy the statement as soon as possible. See
     // DatabaseConnection_sqlite::PDOPrepare() for explanation.
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
index d523bd0..5d746f3 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
@@ -150,7 +150,7 @@ function testStandalonePoFile() {
 
     // The database should now contain 6 customized strings (two imported
     // strings are not translated).
-    $count = db_query('SELECT lid FROM {locales_target} WHERE customized = :custom', array(':custom' => 1))->rowCount();
+    $count = db_query('SELECT COUNT(*) FROM {locales_target} WHERE customized = :custom', array(':custom' => 1))->fetchField();
     $this->assertEqual($count, 6, 'Customized translations successfully imported.');
 
     // Try importing a .po file with overriding strings, and ensure existing
diff --git a/core/modules/locale/locale.translation.inc b/core/modules/locale/locale.translation.inc
index dc62a19..5ebe427 100644
--- a/core/modules/locale/locale.translation.inc
+++ b/core/modules/locale/locale.translation.inc
@@ -54,17 +54,17 @@ function locale_translation_get_projects($project_names = array()) {
 
   if (empty($projects)) {
     // Get project data from the database.
-    $result = db_query('SELECT name, project_type, core, version, server_pattern, status FROM {locale_project}');
+    $row_count = db_query_range('SELECT 1 FROM {locale_project}', 0, 1)->fetchField();
 
     // http://drupal.org/node/1777106 is a follow-up issue to make the check for
     // possible out-of-date project information more robust.
-    if ($result->rowCount() == 0 && \Drupal::moduleHandler()->moduleExists('update')) {
+    if ($row_count == 0 && \Drupal::moduleHandler()->moduleExists('update')) {
       module_load_include('compare.inc', 'locale');
       // At least the core project should be in the database, so we build the
       // data if none are found.
       locale_translation_build_projects();
-      $result = db_query('SELECT name, project_type, core, version, server_pattern, status FROM {locale_project}');
     }
+    $result = db_query('SELECT name, project_type, core, version, server_pattern, status FROM {locale_project}');
 
     foreach ($result as $project) {
       $projects[$project->name] = $project;
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeStatement.php b/core/modules/migrate/tests/Drupal/migrate/Tests/FakeStatement.php
index 9088c50..fdcf113 100644
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeStatement.php
+++ b/core/modules/migrate/tests/Drupal/migrate/Tests/FakeStatement.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\migrate\Tests;
 
+use Drupal\Core\Database\RowCountException;
 use Drupal\Core\Database\StatementInterface;
 
 /**
@@ -32,7 +33,7 @@ public function getQueryString() {
    * {@inheritdoc}
    */
   public function rowCount() {
-    return $this->count();
+    throw new RowCountException();
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Tests/Database/SelectComplexTest.php b/core/modules/system/lib/Drupal/system/Tests/Database/SelectComplexTest.php
index d764696..7e7d24d 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Database/SelectComplexTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Database/SelectComplexTest.php
@@ -2,11 +2,13 @@
 
 /**
  * @file
- * Definition of Drupal\system\Tests\Database\SelectComplexTest.
+ * Contains \Drupal\system\Tests\Database\SelectComplexTest.
  */
 
 namespace Drupal\system\Tests\Database;
 
+use \Drupal\Core\Database\RowCountException;
+
 /**
  * Tests more complex select statements.
  */
@@ -156,9 +158,9 @@ function testRange() {
     $query->addField('test', 'name');
     $query->addField('test', 'age', 'age');
     $query->range(0, 2);
-    $result = $query->execute();
+    $query_result = $query->countQuery()->execute()->fetchField();
 
-    $this->assertEqual($result->rowCount(), 2, 'Returned the correct number of rows.');
+    $this->assertEqual($query_result, 2, 'Returned the correct number of rows.');
   }
 
   /**
@@ -168,9 +170,9 @@ function testDistinct() {
     $query = db_select('test_task');
     $query->addField('test_task', 'task');
     $query->distinct();
-    $result = $query->execute();
+    $query_result = $query->countQuery()->execute()->fetchField();
 
-    $this->assertEqual($result->rowCount(), 6, 'Returned the correct number of rows.');
+    $this->assertEqual($query_result, 6, 'Returned the correct number of rows.');
   }
 
   /**
@@ -363,4 +365,22 @@ function testJoinSubquery() {
     $pos2 = strpos($str, 'db_condition_placeholder_0', $pos + 1);
     $this->assertFalse($pos2, 'Condition placeholder is not repeated.');
   }
+
+  /**
+   * Tests that rowCount() throws exception on SELECT query.
+   */
+  function testSelectWithRowCount() {
+    $query = db_select('test');
+    $query->addField('test', 'name');
+    $result = $query->execute();
+    try {
+      $result->rowCount();
+      $exception = FALSE;
+    }
+    catch (RowCountException $e) {
+      $exception = TRUE;
+    }
+    $this->assertTrue($exception, 'Exception was thrown');
+  }
+
 }