I wrote some code that was pulling batches of events off a queue, doing some processing and then writing them out to HDFS. The inner loop was something like:

I wrote some code that was pulling batches of events off a queue, doing some processing and then writing them out to HDFS. The inner loop was something like: while message: converted_event = new Event() for event in message.events(): converted_event.set_fields(event) write_to_hdfs(converted_event) Can you spot the bug? Led to a month of corrupted data before I noticed.. The `set_fields` method does not clear all fields, so every event had more and more junk data than the one before it. All because i thought i would be clever and get some performance gains by initializing `converted_event` outside the inner loop.