diff --git a/fail2ban-regex b/fail2ban-regex
index e19b1bc9..ff4bbd10 100755
--- a/fail2ban-regex
+++ b/fail2ban-regex
@@ -240,7 +240,7 @@ class Fail2banRegex(object):
 
 	def process(self, test_lines):
 
-		for line in test_lines:
+		for line_no, line in enumerate(test_lines):
 			if line.startswith('#') or not line.strip():
 				# skip comment and empty lines
 				continue
@@ -256,6 +256,9 @@ class Fail2banRegex(object):
 					self._line_stats.missed_lines.append(line)
 			self._line_stats.tested += 1
 
+			if line_no % 10 == 0:
+				self._filter.dateDetector.sortTemplate()
+
 	def printLines(self, ltype):
 		lstats = self._line_stats
 		assert(len(lstats.missed_lines) == lstats.tested - (lstats.matched + lstats.ignored))