Snorkel label function failed error "label function returned -1 for all rows"

TL;DR

Fix this in Snorkel by acting on the exact message first: run the label function on a handful of rows by hand, fix the condition that never fires (usually a renamed column or a threshold no row reaches), and confirm it returns a real class for at least some rows before rerunning the full pass. Do not rerun the whole job unchanged, because the same inputs produce the same failure. Prove the fix on one item, then rerun the full scope and reconcile the counts.

label function returned -1 for all rows

Use this when

• The operation in Snorkel fails with this exact message: label function returned -1 for all rows.
• The same failure repeats on retry with unchanged inputs.
• A review, export or check is blocked until this item completes.

Not for this skill when

• The message is a permission or outage notice from the platform. Resolve that first, then return here if this error remains.
• The operation completes and you only disagree with its output. That is a quality review, not this failure.

Steps

1. Reproduce the failure with the smallest scope that still shows it in Snorkel, and copy the full message plus the item, user or metric involved into the run notes. Verify: the error is reproduced on demand with a named item, not only seen in a log.
2. Apply the specific fix for this error: run the label function on a handful of rows by hand, fix the condition that never fires (usually a renamed column or a threshold no row reaches), and confirm it returns a real class for at least some rows before rerunning the full pass. Verify: the label distribution shows non abstain labels on the sample rows.
3. Check the neighbouring items that share the same config, ontology, baseline or credential, because this class of failure rarely affects only one item. Verify: the neighbouring items are listed and each is marked affected or clear.
4. Rerun the original operation in Snorkel on the previously failing scope, watching for the same message rather than assuming success from a quiet log. Verify: the operation completes and the original message does not appear.
5. Compare the result counts, decisions or alerts against the source in Snorkel so a silent partial success is caught before sign off. Verify: counts match the source or every difference is named and explained.
6. Record the fix, the triggering input and the verification result on the item so the next occurrence is recognised immediately. Verify: the record names the error, the fix applied and the evidence of success.

Why it happens

In Snorkel the value -1 means abstain; when every row abstains, no pattern in the function matched any row.

Variant phrasings

label function returned -1 for all rows

The verbatim form searchers paste from the terminal or console. Treat it identically: same fix, same single item proof, then the full rerun.

How to fix: Snorkel label function failed error "label function returned -1 for all rows"

The how-to phrasing for the same failure in Snorkel. The steps above apply unchanged; start at the reproduction step rather than skipping to the rerun.

Snorkel troubleshooting for this failure

The symptom-first phrasing used when the console hides the full message. Surface the full message first, confirm it matches the code block above, then follow the steps.

Compatibility: Snorkel at current versions, plus the platform API or console the query names; no extra tooling beyond a text editor and the source system access needed to verify counts.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst47bfaH49sXBEgq6PcD6Rw

Resolved from the public thread: https://vectle.com/posts/pst47bfaH49sXBEgq6PcD6Rw

Thread query: Snorkel label function failed error "label function returned -1 for all rows"

TL;DR: Fix this in Snorkel by acting on the exact message first: run the label function on a handful of rows by hand, fix the condition that never fires (usually a renamed column or a threshold no row reaches), and confirm it returns a real class for at least some rows before rerunning the full pass. Do not rerun the whole job unchanged, because the same inputs produce the same failure. Prove the fix on one item, then rerun the full scope and reconcile the counts.