diff --git a/include/Core/Config.php b/include/Core/Config.php
index 1d0e66ddc0..2e92b119a4 100644
--- a/include/Core/Config.php
+++ b/include/Core/Config.php
@@ -139,24 +139,31 @@ class Config {
 	public static function set($family, $key, $value) {
 		$a = get_app();
 
+		// We always store boolean values as integer.
+		// And when fetching we don't convert them back to boolean.
+		// So we have to do the conversion here so that the compare below works.
+		$dbvalue = (is_bool($value) ? (string)intval($value) : $value);
+
+		// Convert the numeric values to string to make the compare work
+		$dbvalue = (is_numeric($value) ? (string)$value : $dbvalue);
+
 		$stored = self::get($family, $key);
 
-		if ($stored === $value) {
+		if ($stored === $dbvalue) {
 			return true;
 		}
 
 		if ($family === 'config') {
-			$a->config[$key] = $value;
+			$a->config[$key] = $dbvalue;
 		} elseif ($family != 'system') {
-			$a->config[$family][$key] = $value;
+			$a->config[$family][$key] = $dbvalue;
 		}
 
 		// Assign the just added value to the cache
-		self::$cache[$family][$key] = $value;
+		self::$cache[$family][$key] = $dbvalue;
 
 		// manage array value
-		$dbvalue = (is_array($value) ? serialize($value) : $value);
-		$dbvalue = (is_bool($dbvalue) ? intval($dbvalue) : $dbvalue);
+		$dbvalue = (is_array($value) ? serialize($value) : $dbvalue);
 
 		if (is_null($stored)) {
 			$ret = q("INSERT INTO `config` (`cat`, `k`, `v`) VALUES ('%s', '%s', '%s') ON DUPLICATE KEY UPDATE `v` = '%s'",
diff --git a/mod/admin.php b/mod/admin.php
index b1bc96fd4f..13a00ff6aa 100644
--- a/mod/admin.php
+++ b/mod/admin.php
@@ -6,6 +6,7 @@
  * @brief Friendica admin
  */
 
+use \Friendica\Core\Config;
 
 require_once("include/enotify.php");
 require_once("include/text.php");
@@ -948,6 +949,16 @@ function admin_page_site(App $a) {
 
 	$diaspora_able = ($a->get_path() == "");
 
+	$optimize_max_tablesize = Config::get('system','optimize_max_tablesize', 100);
+
+	if ($optimize_max_tablesize < -1) {
+		$optimize_max_tablesize = -1;
+	}
+
+	if ($optimize_max_tablesize == 0) {
+		$optimize_max_tablesize = 100;
+	}
+
 	$t = get_markup_template("admin_site.tpl");
 	return replace_macros($t, array(
 		'$title' => t('Administration'),
@@ -1019,7 +1030,7 @@ function admin_page_site(App $a) {
 		'$poll_interval'	=> array('poll_interval', t("Poll interval"), (x(get_config('system','poll_interval'))?get_config('system','poll_interval'):2), t("Delay background polling processes by this many seconds to reduce system load. If 0, use delivery interval.")),
 		'$maxloadavg'		=> array('maxloadavg', t("Maximum Load Average"), ((intval(get_config('system','maxloadavg')) > 0)?get_config('system','maxloadavg'):50), t("Maximum system load before delivery and poll processes are deferred - default 50.")),
 		'$maxloadavg_frontend'	=> array('maxloadavg_frontend', t("Maximum Load Average (Frontend)"), ((intval(get_config('system','maxloadavg_frontend')) > 0)?get_config('system','maxloadavg_frontend'):50), t("Maximum system load before the frontend quits service - default 50.")),
-		'$optimize_max_tablesize'=> array('optimize_max_tablesize', t("Maximum table size for optimization"), ((intval(get_config('system','optimize_max_tablesize')) > 0)?get_config('system','optimize_max_tablesize'):100), t("Maximum table size (in MB) for the automatic optimization - default 100 MB. Enter -1 to disable it.")),
+		'$optimize_max_tablesize'=> array('optimize_max_tablesize', t("Maximum table size for optimization"), $optimize_max_tablesize, t("Maximum table size (in MB) for the automatic optimization - default 100 MB. Enter -1 to disable it.")),
 		'$optimize_fragmentation'=> array('optimize_fragmentation', t("Minimum level of fragmentation"), ((intval(get_config('system','optimize_fragmentation')) > 0)?get_config('system','optimize_fragmentation'):30), t("Minimum fragmenation level to start the automatic optimization - default value is 30%.")),
 
 		'$poco_completion'	=> array('poco_completion', t("Periodical check of global contacts"), get_config('system','poco_completion'), t("If enabled, the global contacts are checked periodically for missing or outdated data and the vitality of the contacts and servers.")),