diff --git a/pytools/log.py b/pytools/log.py
index 4a78699a4685aff1a72e0cdb947b8b919f20c6ff..b6d40403b13f8ca28f4bb2ce6f8c702f7a176450 100644
--- a/pytools/log.py
+++ b/pytools/log.py
@@ -476,7 +476,7 @@ class LogManager(object):
             if self.db_conn is not None:
                 try:
                     self.db_conn.execute("insert into %s values (?,?,?)" % name,
-                            (self.tick_count, self.rank, value))
+                            (self.tick_count, self.rank, float(value)))
                 except:
                     print "while adding datapoint for '%s':" % name
                     raise