diff --git a/pywb/cdx/cdxobject.py b/pywb/cdx/cdxobject.py
index 6e76252a..7eb57180 100644
--- a/pywb/cdx/cdxobject.py
+++ b/pywb/cdx/cdxobject.py
@@ -107,6 +107,7 @@ class CDXObject(OrderedDict):
 
         cdxline = cdxline.rstrip()
         self._from_json = False
+        self._cached_json = None
 
         # Allows for filling the fields later or in a custom way
         if not cdxline:
@@ -157,6 +158,9 @@ class CDXObject(OrderedDict):
         # force regen on next __str__ call
         self.cdxline = None
 
+        # force regen on next to_json() call
+        self._cached_json = None
+
     def is_revisit(self):
         """return ``True`` if this record is a revisit record."""
         return (self.get(MIMETYPE) == 'warc/revisit' or
@@ -174,7 +178,7 @@ class CDXObject(OrderedDict):
             return str(self) + '\n'
 
         try:
-            result = ' '.join(self[x] for x in fields) + '\n'
+            result = ' '.join(str(self[x]) for x in fields) + '\n'
         except KeyError as ke:
             msg = 'Invalid field "{0}" found in fields= argument'
             msg = msg.format(ke.message)
@@ -182,7 +186,6 @@ class CDXObject(OrderedDict):
 
         return result
 
-
     def to_json(self, fields=None):
         return self.conv_to_json(self, fields)
 
@@ -213,7 +216,7 @@ class CDXObject(OrderedDict):
             return self.cdxline.decode('utf-8')
 
         if not self._from_json:
-            return ' '.join(val for n, val in six.iteritems(self))
+            return ' '.join(str(val) for val in six.itervalues(self))
         else:
             return json_encode(self)
 
@@ -223,7 +226,13 @@ class CDXObject(OrderedDict):
         return prefix + self.conv_to_json(dupe, fields)
 
     def __lt__(self, other):
-        return str(self) < str(other)
+        if not self._cached_json:
+            self._cached_json = self.to_json()
+
+        if not other._cached_json:
+            other._cached_json = other.to_json()
+
+        return self._cached_json < other._cached_json
 
 
 #=================================================================
diff --git a/pywb/cdx/cdxserver.py b/pywb/cdx/cdxserver.py
index 49cf48e6..bfdf5741 100644
--- a/pywb/cdx/cdxserver.py
+++ b/pywb/cdx/cdxserver.py
@@ -69,7 +69,7 @@ class BaseCDXServer(object):
 
     def load_cdx(self, **params):
         params['_url_canon'] = self.url_canon
-        query = CDXQuery(**params)
+        query = CDXQuery(params)
 
         #key, end_key = self._calc_search_keys(query)
         #query.set_key(key, end_key)
diff --git a/pywb/cdx/cdxsource.py b/pywb/cdx/cdxsource.py
index 272d3c41..95fc2616 100644
--- a/pywb/cdx/cdxsource.py
+++ b/pywb/cdx/cdxsource.py
@@ -60,8 +60,8 @@ class RemoteCDXSource(CDXSource):
             remote_query = query
         else:
             # Only send url and matchType to remote
-            remote_query = CDXQuery(url=query.url,
-                                    matchType=query.match_type)
+            remote_query = CDXQuery(dict(url=query.url,
+                                         matchType=query.match_type))
 
         urlparams = remote_query.urlencode()
 
diff --git a/pywb/cdx/query.py b/pywb/cdx/query.py
index 3058630c..4e82a5de 100644
--- a/pywb/cdx/query.py
+++ b/pywb/cdx/query.py
@@ -5,8 +5,8 @@ from pywb.utils.canonicalize import calc_search_range
 
 #=================================================================
 class CDXQuery(object):
-    def __init__(self, **kwargs):
-        self.params = kwargs
+    def __init__(self, params):
+        self.params = params
         url = self.url
         if not self.params.get('matchType'):
             if url.startswith('*.'):
@@ -18,7 +18,7 @@ class CDXQuery(object):
             else:
                 self.params['matchType'] = 'exact'
 
-        start, end = calc_search_range(url=url,
+        start, end = calc_search_range(url=self.url,
                                        match_type=self.params['matchType'],
                                        url_canon=self.params.get('_url_canon'))
 
diff --git a/pywb/cdx/test/test_lazy_ops.py b/pywb/cdx/test/test_lazy_ops.py
index e5c64ea5..d31f27b6 100644
--- a/pywb/cdx/test/test_lazy_ops.py
+++ b/pywb/cdx/test/test_lazy_ops.py
@@ -29,7 +29,7 @@ def lazy_cdx_load(**params):
     params['custom_ops'] = [raise_access_exception]
 
     cdx_iter = cdx_load(['bogus ignored'],
-                        CDXQuery(**params),
+                        CDXQuery(params),
                         process=True)
 
     # exception happens on first access attempt