diff --git a/CRM/Utils/Cache/SqlGroup.php b/CRM/Utils/Cache/SqlGroup.php
index 3b983ae10632..e476f3b8320a 100644
--- a/CRM/Utils/Cache/SqlGroup.php
+++ b/CRM/Utils/Cache/SqlGroup.php
@@ -38,8 +38,11 @@
  */
 class CRM_Utils_Cache_SqlGroup implements CRM_Utils_Cache_Interface {
 
+  // 6*60*60
+  const DEFAULT_TTL = 21600;
+
+  const TS_FMT = 'Y-m-d H:i:s';
   use CRM_Utils_Cache_NaiveMultipleTrait; // TODO Consider native implementation.
-  use CRM_Utils_Cache_NaiveHasTrait; // TODO Native implementation
 
   /**
    * The host name of the memcached server.
@@ -56,7 +59,18 @@ class CRM_Utils_Cache_SqlGroup implements CRM_Utils_Cache_Interface {
   /**
    * @var array in-memory cache to optimize redundant get()s
    */
-  protected $frontCache;
+  protected $valueCache;
+
+  /**
+   * @var array in-memory cache to optimize redundant get()s
+   *   Note: expiresCache[$key]===NULL means cache-miss
+   */
+  protected $expiresCache;
+
+  /**
+   * @var string
+   */
+  protected $table;
 
   /**
    * Constructor.
@@ -71,6 +85,7 @@ class CRM_Utils_Cache_SqlGroup implements CRM_Utils_Cache_Interface {
    * @return \CRM_Utils_Cache_SqlGroup
    */
   public function __construct($config) {
+    $this->table = CRM_Core_DAO_Cache::getTableName();
     if (isset($config['group'])) {
       $this->group = $config['group'];
     }
@@ -83,7 +98,7 @@ public function __construct($config) {
     else {
       $this->componentID = NULL;
     }
-    $this->frontCache = array();
+    $this->valueCache = array();
     if (CRM_Utils_Array::value('prefetch', $config, TRUE)) {
       $this->prefetch();
     }
@@ -96,11 +111,53 @@ public function __construct($config) {
    * @return bool
    */
   public function set($key, $value, $ttl = NULL) {
-    if ($ttl !== NULL) {
-      throw new \RuntimeException("FIXME: " . __CLASS__ . "::set() should support non-NULL TTL");
+    CRM_Utils_Cache::assertValidKey($key);
+
+    //    CRM_Core_BAO_Cache::setItem($value, $this->group, $key, $this->componentID);
+    $lock = Civi::lockManager()->acquire("cache.{$this->group}_{$key}._null");
+    if (!$lock->isAcquired()) {
+      throw new \CRM_Utils_Cache_CacheException("SqlGroup: Failed to acquire lock on cache key.");
     }
-    CRM_Core_BAO_Cache::setItem($value, $this->group, $key, $this->componentID);
-    $this->frontCache[$key] = $value;
+
+    $dataExists = CRM_Core_DAO::singleValueQuery("SELECT COUNT(*) FROM {$this->table} WHERE {$this->where($key)}");
+    $now = date(self::TS_FMT); // FIXME - Use SQL NOW() or CRM_Utils_Time?
+    $expires = $this->convertTtlToExpires($ttl);
+
+    $dataSerialized = CRM_Core_BAO_Cache::encode($value);
+
+    // This table has a wonky index, so we cannot use REPLACE or
+    // "INSERT ... ON DUPE". Instead, use SELECT+(INSERT|UPDATE).
+    if ($dataExists) {
+      $sql = "UPDATE {$this->table} SET data = %1, created_date = %2, expired_date = %3 WHERE {$this->where($key)}";
+      $args = array(
+        1 => array($dataSerialized, 'String'),
+        2 => array($now, 'String'),
+        3 => array(date(self::TS_FMT, $expires), 'String'),
+      );
+      // printf("WRITE: %s\n", CRM_Core_DAO::composeQuery($sql, $args));
+      $dao = CRM_Core_DAO::executeQuery($sql, $args, FALSE, NULL, FALSE, FALSE);
+    }
+    else {
+      $insert = CRM_Utils_SQL_Insert::into($this->table)
+        ->row(array(
+          'group_name' => $this->group,
+          'path' => $key,
+          'component_id' => NULL,
+          'data' => $dataSerialized,
+          'created_date' => $now,
+          'expired_date' => date(self::TS_FMT, $expires),
+        ));
+      $sql = $insert->toSQL();
+      // printf("WRITE: %s\n", $sql);
+      $dao = CRM_Core_DAO::executeQuery($sql, array(), FALSE, NULL, FALSE, FALSE);
+    }
+
+    $lock->release();
+
+    $dao->free();
+
+    $this->valueCache[$key] = CRM_Core_BAO_Cache::decode($dataSerialized);
+    $this->expiresCache[$key] = $expires;
     return TRUE;
   }
 
@@ -111,13 +168,21 @@ public function set($key, $value, $ttl = NULL) {
    * @return mixed
    */
   public function get($key, $default = NULL) {
-    if ($default !== NULL) {
-      throw new \RuntimeException("FIXME: " . __CLASS__ . "::get() only supports NULL default");
+    CRM_Utils_Cache::assertValidKey($key);
+    if (!isset($this->expiresCache[$key]) || time() >= $this->expiresCache[$key]) {
+      $sql = "SELECT path, data, UNIX_TIMESTAMP(expired_date) as expires FROM {$this->table} WHERE " . $this->where($key);
+      $dao = CRM_Core_DAO::executeQuery($sql);
+      while ($dao->fetch()) {
+        $this->expiresCache[$key] = $dao->expires;
+        $this->valueCache[$key] = CRM_Core_BAO_Cache::decode($dao->data);
+      }
+      $dao->free();
     }
-    if (!array_key_exists($key, $this->frontCache)) {
-      $this->frontCache[$key] = CRM_Core_BAO_Cache::getItem($this->group, $key, $this->componentID);
-    }
-    return $this->frontCache[$key];
+    return (isset($this->expiresCache[$key]) && time() < $this->expiresCache[$key]) ? $this->reobjectify($this->valueCache[$key]) : $default;
+  }
+
+  private function reobjectify($value) {
+    return is_object($value) ? unserialize(serialize($value)) : $value;
   }
 
   /**
@@ -127,7 +192,17 @@ public function get($key, $default = NULL) {
    * @return mixed
    */
   public function getFromFrontCache($key, $default = NULL) {
-    return CRM_Utils_Array::value($key, $this->frontCache, $default);
+    if (isset($this->expiresCache[$key]) && time() < $this->expiresCache[$key] && $this->valueCache[$key]) {
+      return $this->reobjectify($this->valueCache[$key]);
+    }
+    else {
+      return $default;
+    }
+  }
+
+  public function has($key) {
+    $this->get($key);
+    return isset($this->expiresCache[$key]) && time() < $this->expiresCache[$key];
   }
 
   /**
@@ -135,18 +210,17 @@ public function getFromFrontCache($key, $default = NULL) {
    * @return bool
    */
   public function delete($key) {
-    CRM_Core_BAO_Cache::deleteGroup($this->group, $key, FALSE);
-    CRM_Core_BAO_Cache::$_cache = NULL; // FIXME: remove multitier cache
-    CRM_Utils_Cache::singleton()->flush(); // FIXME: remove multitier cache
-    unset($this->frontCache[$key]);
+    CRM_Utils_Cache::assertValidKey($key);
+    CRM_Core_DAO::executeQuery("DELETE FROM {$this->table} WHERE {$this->where($key)}");
+    unset($this->valueCache[$key]);
+    unset($this->expiresCache[$key]);
     return TRUE;
   }
 
   public function flush() {
-    CRM_Core_BAO_Cache::deleteGroup($this->group, NULL, FALSE);
-    CRM_Core_BAO_Cache::$_cache = NULL; // FIXME: remove multitier cache
-    CRM_Utils_Cache::singleton()->flush(); // FIXME: remove multitier cache
-    $this->frontCache = array();
+    CRM_Core_DAO::executeQuery("DELETE FROM {$this->table} WHERE {$this->where()}");
+    $this->valueCache = array();
+    $this->expiresCache = array();
     return TRUE;
   }
 
@@ -155,7 +229,47 @@ public function clear() {
   }
 
   public function prefetch() {
-    $this->frontCache = CRM_Core_BAO_Cache::getItems($this->group, $this->componentID);
+    $dao = CRM_Core_DAO::executeQuery("SELECT path, data, UNIX_TIMESTAMP(expired_date) AS expires FROM {$this->table} WHERE " . $this->where(NULL));
+    $this->valueCache = array();
+    $this->expiresCache = array();
+    while ($dao->fetch()) {
+      $this->valueCache[$dao->path] = CRM_Core_BAO_Cache::decode($dao->data);
+      $this->expiresCache[$dao->path] = $dao->expires;
+    }
+    $dao->free();
+  }
+
+  protected function where($path = NULL) {
+    $clauses = array();
+    $clauses[] = ('group_name = "' . CRM_Core_DAO::escapeString($this->group) . '"');
+    if ($path) {
+      $clauses[] = ('path = "' . CRM_Core_DAO::escapeString($path) . '"');
+    }
+    return $clauses ? implode(' AND ', $clauses) : '(1)';
+  }
+
+  /**
+   * Translate a TTL to a concrete expiration time.
+   *
+   * @param NULL|int|DateInterval $ttl
+   * @return int
+   *   Timestamp (seconds since epoch).
+   * @throws \CRM_Utils_Cache_InvalidArgumentException
+   */
+  private function convertTtlToExpires($ttl) {
+    if ($ttl === NULL) {
+      $ttl = self::DEFAULT_TTL;
+    }
+
+    if (is_int($ttl)) {
+      return time() + $ttl;
+    }
+    elseif ($ttl instanceof DateInterval) {
+      return date_add(new DateTime(), $ttl)->getTimestamp();
+    }
+    else {
+      throw new CRM_Utils_Cache_InvalidArgumentException("Invalid cache TTL");
+    }
   }
 
 }
diff --git a/tests/phpunit/CRM/Utils/Cache/SqlGroupTest.php b/tests/phpunit/CRM/Utils/Cache/SqlGroupTest.php
index 85de83acc698..77f31a26b4ae 100644
--- a/tests/phpunit/CRM/Utils/Cache/SqlGroupTest.php
+++ b/tests/phpunit/CRM/Utils/Cache/SqlGroupTest.php
@@ -47,7 +47,9 @@ public function testTwoInstance() {
     ));
     $fooValue = array('whiz' => 'bang', 'bar' => 3);
     $a->set('foo', $fooValue);
-    $this->assertEquals($a->get('foo'), array('whiz' => 'bang', 'bar' => 3));
+    $getValue = $a->get('foo');
+    $expectValue = array('whiz' => 'bang', 'bar' => 3);
+    $this->assertEquals($getValue, $expectValue);
 
     $b = new CRM_Utils_Cache_SqlGroup(array(
       'group' => 'testTwoInstance',
diff --git a/tests/phpunit/E2E/Cache/SqlGroupTest.php b/tests/phpunit/E2E/Cache/SqlGroupTest.php
new file mode 100644
index 000000000000..8ed89e028990
--- /dev/null
+++ b/tests/phpunit/E2E/Cache/SqlGroupTest.php
@@ -0,0 +1,41 @@
+<?php
+/*
+ +--------------------------------------------------------------------+
+ | CiviCRM version 5                                                  |
+ +--------------------------------------------------------------------+
+ | Copyright CiviCRM LLC (c) 2004-2018                                |
+ +--------------------------------------------------------------------+
+ | This file is a part of CiviCRM.                                    |
+ |                                                                    |
+ | CiviCRM is free software; you can copy, modify, and distribute it  |
+ | under the terms of the GNU Affero General Public License           |
+ | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
+ |                                                                    |
+ | CiviCRM is distributed in the hope that it will be useful, but     |
+ | WITHOUT ANY WARRANTY; without even the implied warranty of         |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
+ | See the GNU Affero General Public License for more details.        |
+ |                                                                    |
+ | You should have received a copy of the GNU Affero General Public   |
+ | License along with this program; if not, contact CiviCRM LLC       |
+ | at info[AT]civicrm[DOT]org. If you have questions about the        |
+ | GNU Affero General Public License or the licensing of CiviCRM,     |
+ | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
+ +--------------------------------------------------------------------+
+ */
+
+/**
+ * Verify that CRM_Utils_Cache_SqlGroup complies with PSR-16.
+ *
+ * @group e2e
+ */
+class E2E_Cache_SqlGroupTest extends E2E_Cache_CacheTestCase {
+
+  public function createSimpleCache() {
+    return CRM_Utils_Cache::create([
+      'name' => 'e2e sqlgroup test',
+      'type' => ['SqlGroup'],
+    ]);
+  }
+
+}