diff --git a/src/index_rank.py b/src/index_rank.py
index ba5e8d2..f17d199 100755
--- a/src/index_rank.py
+++ b/src/index_rank.py
@@ -3,7 +3,9 @@
 import sys
 import lib_common as mylib
 import bundle_combine  # get_evaluated
-import index_app_names
+import index_app_names  # get_name
+
+MAX_RANKING_LIMIT = 500
 
 
 def fname_app_summary():
@@ -35,35 +37,73 @@ def json_to_list(json):
     ]
 
 
-def write_summary_index(index, bundle_ids, deleteOnly=False):
-    for bid in bundle_ids:
-        # delete old value
-        mylib.try_del(index, [bid])
-        if deleteOnly:
-            continue
-        # set new value
-        index[bid] = json_to_list(bundle_combine.get_evaluated(bid))
-
-    # sum of counts
-    mylib.try_del(index, ['_sum'])
-    total = [0, 0]
-    for val in index.values():
-        total[0] += val[0]
-        total[1] += val[8]
-    index['_sum'] = total
-    mylib.json_write(fname_app_summary(), index, pretty=False)
-    mylib.try_del(index, ['_sum'])
+def update_summary_index(index, bundle_ids, deleteOnly=False):
+    did_change = False
+    if deleteOnly:
+        did_change = mylib.try_del(index, bundle_ids)
+    else:
+        for bid in bundle_ids:
+            # set new value
+            new_value = json_to_list(bundle_combine.get_evaluated(bid))
+            try:
+                if new_value == index[bid]:
+                    continue
+            except KeyError:
+                pass
+            index[bid] = new_value
+            did_change = True
+    if did_change:
+        mylib.try_del(index, ['_sum'])
+        total = [0, 0]
+        for val in index.values():
+            total[0] += val[0]
+            total[1] += val[8]
+        index['_sum'] = total
+        mylib.json_write(fname_app_summary(), index, pretty=False)
+        mylib.try_del(index, ['_sum'])
+    return did_change
 
 
-def write_ranking_list(index):
+def write_ranking_category_list(index, affected_ids):
+    reset = affected_ids == ['*']
+
+    def category_affected(category_bundle_ids):
+        if reset or len(affected_ids) > 10:
+            return True
+        for x in affected_ids:
+            if x in category_bundle_ids:
+                return True
+        return False
+
+    pth = mylib.path_data_index('rank')
+    if reset:
+        mylib.rm_dir(pth)
+    mylib.mkdir(pth)
+    for _, json in mylib.enum_categories():
+        cid, cname = json['meta']
+        ids = [bid for bid, _ in json['apps']]
+        ret = []
+        if len(ids) > 0 and category_affected(ids):
+            for x in index:
+                if x[0] not in ids:
+                    continue
+                ret.append(x)
+                if len(ids) == 0 or len(ret) >= MAX_RANKING_LIMIT:
+                    break
+        mylib.json_write(mylib.path_add(pth, 'id_{}.json'.format(cid)),
+                         ret, pretty=False)
+
+
+def write_ranking_list(index, affected_ids):
     ret = []
     for bid, values in index.items():
         ret.append([bid, index_app_names.get_name(bid)] + values)
         del(values[8:])
     ret.sort(key=lambda x: -x[2 + 10])  # sort by last update
+    write_ranking_category_list(ret, affected_ids)
     # TODO: doesnt scale well, 100'000 apps ~> 12mb
-    if len(ret) > 500:  # limit to most recent X entries
-        ret = ret[:500]
+    if len(ret) > MAX_RANKING_LIMIT:  # limit to most recent X entries
+        ret = ret[:MAX_RANKING_LIMIT]
     # mylib.sort_by_name(ret, 1)
     mylib.json_write(fname_ranking_list(), ret, pretty=False)
 
@@ -112,9 +152,9 @@ def process(bundle_ids, deleteOnly=False):
 
     index = mylib.json_safe_read(fname, {})
     ids = mylib.appids_in_data(bundle_ids)
-    write_summary_index(index, ids, deleteOnly=deleteOnly)
-    write_ranking_list(index)
-    write_rank_index(index)
+    if update_summary_index(index, ids, deleteOnly=deleteOnly):
+        write_ranking_list(index, bundle_ids)
+        write_rank_index(index)
     print('')