Remove temp. DNS host cache

We now have a better DNS cache solution found within the Symfony layer, which handles any hostname lookup.

runtime/lib/Propel.php

@@ -683,7 +683,7 @@ public static function initConnection($conparams, $name, $defaultClass = Propel:
         }
 
         try {
-            $con = new $classname(self::resolveCachedDsnHost($dsn), $user, $password, $driver_options);
+            $con = new $classname($dsn, $user, $password, $driver_options);
             $con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
             $con->setAttribute(PropelPDO::PROPEL_ATTR_CONNECTION_NAME, $name);
 
@@ -944,33 +944,6 @@ public static function isInstancePoolingEnabled()
     {
         return self::$instancePoolingEnabled;
     }
-
-    /**
-     * Within Lambda we are unable to easily cache DNS records as we do on conventional servers.
-     * As each request creates a new connection, the amount of DNS queries we perform can mount up.
-     * This adds an application-level cache for storing the resolved IP of the desired host (env: CACHE_PDO_HOST_DNS).
-     */
-    private static function resolveCachedDsnHost(string $dsn, int $ttlInSeconds = 300): string
-    {
-        $hostname = \getenv('PROPEL_CACHE_PDO_HOST_DNS');
-
-        if (!$hostname || false === \strpos($dsn, $hostname)) {
-            return $dsn;
-        }
-
-        if (false === \function_exists('apcu_entry')) {
-            return $dsn;
-        }
-
-        $ip = \apcu_entry($hostname, function (string $name): string {
-            if (\class_exists('\MyBuilder\Bundle\LogBundle\Metrics')) {
-                \MyBuilder\Bundle\LogBundle\Metrics::increment('pdo.dns-cache.miss', ['host' => $name]);
-            }
-            return \gethostbyname($name);
-        }, $ttlInSeconds);
-
-        return \str_replace($hostname, $ip, $dsn);
-    }
 }
 
 // Since the Propel class is not a true singleton, this code cannot go into the __construct()