Loading…
14
PSA: tracing model training logs found my data leak in an hour
Had a client model where accuracy tanked on Thursdays only, drove me nuts for 2 weeks. Turned out a scraping pipeline was pulling Thursday-only test set rows into training. Adding a simple hash check on the pipeline side fixed it, has anyone else caught silent dataset contamination like that?
1 comments
Log in to join the discussion
Log In1 Comment
thomas_sanchez7d ago
Thursdays only, huh? Sounds like your data pipeline had a religious commitment to ruining your week. I bet whoever wrote that scraper thought they were being real clever with the date filter too.
Honestly, that kind of bug is the stuff of nightmares. You spend weeks staring at accuracy curves like a crazy person, convinced you're losing your mind, and it turns out some cron job has a scheduling beef with the calendar.
Hash check is the move though. I had a similar thing once where my validation set had a duplicate of the training set, but only for a certain batch ID. Spent three days arguing with my own logs before I gave up and started doing checksums on everything. Now I just assume all pipelines are lying to me until they prove otherwise.
9