OOM during migrate about tracboat HOT 3 OPEN

diff --git a/src/tracboat/cli.py b/src/tracboat/cli.py
index c45c606..eff91a8 100644
--- a/src/tracboat/cli.py
+++ b/src/tracboat/cli.py
@@ -373,9 +373,10 @@ def migrate(ctx, umap, umap_file, fallback_user, trac_uri, ssl_verify,
         LOG.info('loading Trac instance from export file: %s', from_export_file)
         fmt = _detect_format(from_export_file)
         LOG.debug('detected file format: %s', fmt)
-        with codecs.open(from_export_file, 'rb', encoding='utf-8') as export_f:
-            content = export_f.read()
-        project = _loads(content, fmt=fmt)
+        #with codecs.open(from_export_file, 'rb', encoding='utf-8') as export_f:
+        #    content = export_f.read()
+        #project = _loads(content, fmt=fmt)
+        project = pickle.load(open(from_export_file))
     else: