diff --git a/lib/Doctrine/DBAL/Cache/QueryCacheProfile.php b/lib/Doctrine/DBAL/Cache/QueryCacheProfile.php
index 883f3b7c881..a722681ce43 100644
--- a/lib/Doctrine/DBAL/Cache/QueryCacheProfile.php
+++ b/lib/Doctrine/DBAL/Cache/QueryCacheProfile.php
@@ -20,18 +20,19 @@
 namespace Doctrine\DBAL\Cache;
 
 use Doctrine\Common\Cache\Cache;
+use function hash;
+use function serialize;
+use function sha1;
 
 /**
  * Query Cache Profile handles the data relevant for query caching.
  *
  * It is a value object, setter methods return NEW instances.
- *
- * @author Benjamin Eberlei <kontakt@beberlei.de>
  */
 class QueryCacheProfile
 {
     /**
-     * @var \Doctrine\Common\Cache\Cache|null
+     * @var Cache|null
      */
     private $resultCacheDriver;
 
@@ -46,19 +47,18 @@ class QueryCacheProfile
     private $cacheKey;
 
     /**
-     * @param int                               $lifetime
-     * @param string|null                       $cacheKey
-     * @param \Doctrine\Common\Cache\Cache|null $resultCache
+     * @param int         $lifetime
+     * @param string|null $cacheKey
      */
-    public function __construct($lifetime = 0, $cacheKey = null, Cache $resultCache = null)
+    public function __construct($lifetime = 0, $cacheKey = null, ?Cache $resultCache = null)
     {
-        $this->lifetime = $lifetime;
-        $this->cacheKey = $cacheKey;
+        $this->lifetime          = $lifetime;
+        $this->cacheKey          = $cacheKey;
         $this->resultCacheDriver = $resultCache;
     }
 
     /**
-     * @return \Doctrine\Common\Cache\Cache|null
+     * @return Cache|null
      */
     public function getResultCacheDriver()
     {
@@ -76,7 +76,7 @@ public function getLifetime()
     /**
      * @return string
      *
-     * @throws \Doctrine\DBAL\Cache\CacheException
+     * @throws CacheException
      */
     public function getCacheKey()
     {
@@ -102,7 +102,7 @@ public function generateCacheKeys($query, $params, $types, array $connectionPara
         $realCacheKey = 'query=' . $query .
             '&params=' . serialize($params) .
             '&types=' . serialize($types) .
-            '&connectionParams=' . serialize($connectionParams);
+            '&connectionParams=' . hash('sha256', serialize($connectionParams));
 
         // should the key be automatically generated using the inputs or is the cache key set?
         if ($this->cacheKey === null) {
@@ -111,11 +111,10 @@ public function generateCacheKeys($query, $params, $types, array $connectionPara
             $cacheKey = $this->cacheKey;
         }
 
-        return array($cacheKey, $realCacheKey);
+        return [$cacheKey, $realCacheKey];
     }
 
     /**
-     * @param \Doctrine\Common\Cache\Cache $cache
      *
      * @return \Doctrine\DBAL\Cache\QueryCacheProfile
      */
diff --git a/tests/Doctrine/Tests/DBAL/Cache/QueryCacheProfileTest.php b/tests/Doctrine/Tests/DBAL/Cache/QueryCacheProfileTest.php
index 553af666784..5bc77c911c3 100644
--- a/tests/Doctrine/Tests/DBAL/Cache/QueryCacheProfileTest.php
+++ b/tests/Doctrine/Tests/DBAL/Cache/QueryCacheProfileTest.php
@@ -5,15 +5,44 @@
 use Doctrine\DBAL\Cache\QueryCacheProfile;
 use Doctrine\DBAL\ParameterType;
 use Doctrine\Tests\DbalTestCase;
+use function parse_str;
 
 class QueryCacheProfileTest extends DbalTestCase
 {
-    const LIFETIME = 3600;
-    const CACHE_KEY = 'user_specified_cache_key';
+    private const LIFETIME  = 3600;
+    private const CACHE_KEY = 'user_specified_cache_key';
 
-    /** @var QueryCacheProfile */
+    /**
+     * @var QueryCacheProfile
+     */
     private $queryCacheProfile;
 
+    /**
+     * @var string
+     */
+    private $query = 'SELECT * FROM foo WHERE bar = ?';
+
+    /**
+     * @var int[]
+     */
+    private $params = [666];
+
+    /**
+     * @var string[]
+     */
+    private $types = [ParameterType::INTEGER];
+
+    /**
+     * @var string[]
+     */
+    private $connectionParams = [
+            'dbname'   => 'database_name',
+            'user'     => 'database_user',
+            'password' => 'database_password',
+            'host'     => 'database_host',
+            'driver'   => 'database_driver',
+        ];
+
     protected function setUp()
     {
         $this->queryCacheProfile = new QueryCacheProfile(self::LIFETIME, self::CACHE_KEY);
@@ -21,23 +50,11 @@ protected function setUp()
 
     public function testShouldUseTheGivenCacheKeyIfPresent()
     {
-        $query  = 'SELECT * FROM foo WHERE bar = ?';
-        $params = [666];
-        $types  = [ParameterType::INTEGER];
-
-        $connectionParams = array(
-            'dbname'   => 'database_name',
-            'user'     => 'database_user',
-            'password' => 'database_password',
-            'host'     => 'database_host',
-            'driver'   => 'database_driver'
-        );
-
         list($cacheKey) = $this->queryCacheProfile->generateCacheKeys(
-            $query,
-            $params,
-            $types,
-            $connectionParams
+            $this->query,
+            $this->params,
+            $this->types,
+            $this->connectionParams
         );
 
         self::assertEquals(self::CACHE_KEY, $cacheKey, 'The returned cache key should match the given one');
@@ -45,25 +62,13 @@ public function testShouldUseTheGivenCacheKeyIfPresent()
 
     public function testShouldGenerateAnAutomaticKeyIfNoKeyHasBeenGiven()
     {
-        $query  = 'SELECT * FROM foo WHERE bar = ?';
-        $params = [666];
-        $types  = [ParameterType::INTEGER];
-
-        $connectionParams = array(
-            'dbname'   => 'database_name',
-            'user'     => 'database_user',
-            'password' => 'database_password',
-            'host'     => 'database_host',
-            'driver'   => 'database_driver'
-        );
-
         $this->queryCacheProfile = $this->queryCacheProfile->setCacheKey(null);
 
         list($cacheKey) = $this->queryCacheProfile->generateCacheKeys(
-            $query,
-            $params,
-            $types,
-            $connectionParams
+            $this->query,
+            $this->params,
+            $this->types,
+            $this->connectionParams
         );
 
         self::assertNotEquals(
@@ -77,67 +82,64 @@ public function testShouldGenerateAnAutomaticKeyIfNoKeyHasBeenGiven()
 
     public function testShouldGenerateDifferentKeysForSameQueryAndParamsAndDifferentConnections()
     {
-        $query  = 'SELECT * FROM foo WHERE bar = ?';
-        $params = [666];
-        $types  = [ParameterType::INTEGER];
-
-        $connectionParams = array(
-            'dbname'   => 'database_name',
-            'user'     => 'database_user',
-            'password' => 'database_password',
-            'host'     => 'database_host',
-            'driver'   => 'database_driver'
-        );
-
         $this->queryCacheProfile = $this->queryCacheProfile->setCacheKey(null);
 
         list($firstCacheKey) = $this->queryCacheProfile->generateCacheKeys(
-            $query,
-            $params,
-            $types,
-            $connectionParams
+            $this->query,
+            $this->params,
+            $this->types,
+            $this->connectionParams
         );
 
-        $connectionParams['host'] = 'a_different_host';
+        $this->connectionParams['host'] = 'a_different_host';
 
         list($secondCacheKey) = $this->queryCacheProfile->generateCacheKeys(
-            $query,
-            $params,
-            $types,
-            $connectionParams
+            $this->query,
+            $this->params,
+            $this->types,
+            $this->connectionParams
         );
 
         self::assertNotEquals($firstCacheKey, $secondCacheKey, 'Cache keys should be different');
     }
 
-    public function testShouldGenerateSameKeysIfNoneOfTheParamsChanges()
+    public function testConnectionParamsShouldBeHashed()
     {
-        $query  = 'SELECT * FROM foo WHERE bar = ?';
-        $params = [666];
-        $types  = [ParameterType::INTEGER];
+        $this->queryCacheProfile = $this->queryCacheProfile->setCacheKey(null);
 
-        $connectionParams = array(
-            'dbname'   => 'database_name',
-            'user'     => 'database_user',
-            'password' => 'database_password',
-            'host'     => 'database_host',
-            'driver'   => 'database_driver'
+        list($cacheKey, $queryString) = $this->queryCacheProfile->generateCacheKeys(
+            $this->query,
+            $this->params,
+            $this->types,
+            $this->connectionParams
         );
 
+        $params = [];
+        parse_str($queryString, $params);
+
+        self::assertArrayHasKey('connectionParams', $params);
+
+        foreach ($this->connectionParams as $param) {
+            self::assertNotContains($param, $params['connectionParams']);
+        }
+    }
+
+    public function testShouldGenerateSameKeysIfNoneOfTheParamsChanges()
+    {
         $this->queryCacheProfile = $this->queryCacheProfile->setCacheKey(null);
 
         list($firstCacheKey) = $this->queryCacheProfile->generateCacheKeys(
-            $query,
-            $params,
-            $types,
-            $connectionParams
+            $this->query,
+            $this->params,
+            $this->types,
+            $this->connectionParams
         );
 
         list($secondCacheKey) = $this->queryCacheProfile->generateCacheKeys(
-            $query,
-            $params,
-            $types,
-            $connectionParams
+            $this->query,
+            $this->params,
+            $this->types,
+            $this->connectionParams
         );
 
         self::assertEquals($firstCacheKey, $secondCacheKey, 'Cache keys should be the same');