diff --git a/lib/db_revision.py b/lib/db_revision.py
index 8876e7a..11dfecb 100644
--- a/lib/db_revision.py
+++ b/lib/db_revision.py
@@ -22,6 +22,7 @@ class DBRevision:
         ) = row
         self.rev = int(self.rev)
         self._files = None
+        self._hash = None
 
     def __str__(self):
         return f"Rev {self.project}/{self.rev} Md5 {self.unexpanded_srcmd5} {self.commit_time} {self.userid} {self.request_number}"
@@ -159,7 +160,9 @@ class DBRevision:
                     ),
                 )
 
-    def fileshash(self, db):
+    def files_hash(self, db):
+        if self._hash:
+            return self._hash
         m = md5()
         for file_dict in self.files_list(db):
             m.update(
@@ -171,7 +174,8 @@ class DBRevision:
                     + str(file_dict["size"])
                 ).encode("utf-8")
             )
-        return m.hexdigest()
+        self._hash = m.hexdigest()
+        return self._hash
 
     def files_list(self, db):
         if self._files:
diff --git a/lib/importer.py b/lib/importer.py
index 34c5f10..8bd08bf 100644
--- a/lib/importer.py
+++ b/lib/importer.py
@@ -9,10 +9,9 @@ from lib.history import History
 from lib.obs import OBS
 from lib.obs_revision import OBSRevision
 from lib.proxy_sha256 import ProxySHA256, md5, sha256
-from lib.request import Request
 import xml.etree.ElementTree as ET
 from lib.user import User
-
+from lib.tree_builder import TreeBuilder
 
 def _files_hash(hash_alg, dirpath):
     """List of (filepath, md5) for a directory"""
@@ -185,6 +184,7 @@ class Importer:
                     self.obs.request(number).import_into_db(db)
 
         db.conn.commit()
+        TreeBuilder(db).build(self.package)
 
     def import_all_revisions(self, gc):
         # Fetch all the requests and sort them.  Ideally we should
diff --git a/lib/tree_builder.py b/lib/tree_builder.py
new file mode 100644
index 0000000..69d260d
--- /dev/null
+++ b/lib/tree_builder.py
@@ -0,0 +1,38 @@
+from lib.db_revision import DBRevision
+from lib.request import Request
+
+
+class TreeBuilder:
+    def __init__(self, db):
+        self.db = db
+
+    def filtered_revisions(self, project, package):
+        revisions = DBRevision.all_revisions(self.db, project, package)
+        revisions.sort()
+        ret = []
+        prev = None
+        for rev in revisions:
+            if rev.broken: continue
+            if prev and prev.files_hash(self.db) == rev.files_hash(self.db):
+                continue
+            ret.append(rev)
+            prev = rev
+        return ret
+
+
+    def build(self, package):
+        factory_revisions = self.filtered_revisions("openSUSE:Factory", package)
+        source_revisions = dict()
+        for rev in factory_revisions:
+            print(rev, rev.files_hash(self.db))
+            if rev.request_id:
+                req = Request.find(self.db, rev.request_id)
+                print("  ", req)
+                key = f"{req.source_project}/{req.source_package}"
+                if key not in source_revisions:
+                    source_revisions[key] = self.filtered_revisions(
+                        req.source_project, req.source_package
+                    )
+                for rev2 in source_revisions.get(key):
+                    if rev2.files_hash(self.db) == rev.files_hash(self.db):
+                        print("    ", rev2)
diff --git a/tests/tree_test.py b/tests/tree_test.py
index 401ec68..03cd73d 100644
--- a/tests/tree_test.py
+++ b/tests/tree_test.py
@@ -5,7 +5,7 @@ import yaml
 
 from lib.db import DB
 from lib.db_revision import DBRevision
-from lib.request import Request
+from lib.tree_builder import TreeBuilder
 
 
 class TestTreeMethods(unittest.TestCase):
@@ -18,22 +18,7 @@ class TestTreeMethods(unittest.TestCase):
             DBRevision.import_fixture_dict(self.db, rev)
 
     def test_create_tree(self):
-        factory_revisions = DBRevision.all_revisions(self.db, "openSUSE:Factory", "zsh")
-        source_revisions = dict()
-        for rev in sorted(factory_revisions):
-            print(rev, rev.fileshash(self.db))
-            if rev.request_id:
-                req = Request.find(self.db, rev.request_id)
-                print("  ", req)
-                key = f"{req.source_project}/{req.source_package}"
-                if key not in source_revisions:
-                    source_revisions[key] = sorted(
-                        DBRevision.all_revisions(
-                            self.db, req.source_project, req.source_package
-                        )
-                    )
-                for rev2 in source_revisions.get(key):
-                    print(rev2, rev2.fileshash(self.db))
+        TreeBuilder(self.db).build("zsh")
 
 
 if __name__ == "__main__":