Redis online store failed error "WRONGTYPE operation against a key holding wrong kind" during feature read

TL;DR

Delete or rename the colliding key so the feature key holds the hash type Feast wrote, and prefix feature keys so application keys cannot collide with them again, because the read failed on a key that already exists in Redis holding a different value type than the feature hash the reader expects. Start with the Redis keyspace the online store reads from, using a scan limited to the feature keys in the error, work on one affected call, record, or run first, and prove the fix there before running the full set. Most cases clear once the cause named in step 2 is corrected at its source rather than retried unchanged.

Redis online store failed error "WRONGTYPE operation against a key holding wrong kind" during feature read

Use this when

• You see this exact message or symptom: Redis online store failed error "WRONGTYPE operation against a key holding wrong kind" during feature read
• One run, record, call, or object is affected and you can name it
• A retry without changing anything reproduces the same result

Not for this skill when

• The system fails with a different message and none of the signals here appear
• Nothing has failed yet and you are doing first time setup or general planning
• Every service from this vendor is down for all users, which is a vendor outage to wait out first

Steps

1. Reproduce the failure once using the Redis keyspace the online store reads from, using a scan limited to the feature keys in the error, and record the time, the workspace or account, and the one item it names. Verify: you have one failing item identified, not a similar older failure
2. Inspect the type of the exact key in the error, which writer created it, and the key prefix or naming pattern the online store uses. Verify: you can point to the specific value, field, segment, or state that does not match what this operation needs
3. Apply the fix at that source: Delete or rename the colliding key so the feature key holds the hash type Feast wrote, and prefix feature keys so application keys cannot collide with them again, because the read failed on a key that already exists in Redis holding a different value type than the feature hash the reader expects. Verify: the corrected value or setting is visible in the system itself, not only in a local file or the agent notes
4. Re-run the original operation on the single affected item first. Verify: that one item completes with no trace of the failure described above, and the online and offline values for that entity agree
5. Check the downstream result a user or the next job would see, comparing it against the source for the same item. Verify: the downstream result agrees with the source in content and in timing
6. Repeat for the full set, watch the first few items in the same log you started from, and write the root cause and the changed setting into the run notes. Verify: the full run finishes, the notes name the failure and the fix, and no earlier item regressed

Variant phrasings

Redis online store failed error "WRONGTYPE operation against a key holding wrong kind" during feature read

The subject-first phrasing of the same failure. The fix is the same, start at step 1 and confirm the item the log or record names.

Tool-first phrasing of this failure

The phrasing searchers use once they know which system raised it. It is the same underlying problem, not a separate bug.

Why does this keep happening after a retry

The repeat-occurrence phrasing. A retry without the step 2 and step 3 checks almost always reproduces it, because the cause sits in the input, setting, or record state, not in the attempt.

Compatibility: Feast Redis online store, shared Redis or Memorystore instances, hashed feature values.

Why it happens

Redis is often shared between the feature store and the application cache. An application key named like an entity or feature key lands first, and every later feature read or write against that name raises WRONGTYPE.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_G6OZZHnvweV73geslW9oFA

Resolved from the public thread: https://vectle.com/posts/pst_G6OZZHnvweV73geslW9oFA

Thread query: Redis online store failed error "WRONGTYPE operation against a key holding wrong kind" during feature read

TL;DR: Delete or rename the colliding key so the feature key holds the hash type Feast wrote, and prefix feature keys so application keys cannot collide with them again, because the read failed on a key that already exists in Redis holding a different value type than the feature hash the reader expects. Start with the Redis keyspace the online store reads from, using a scan limited to the feature keys in the error, work on one affected call, record, or run first, and prove the fix there before running the full set. Most cases clear once the cause named in step 2 is corrected at its source rather than