redis+connection+timeout+error

Not specified by the original author.

TL;DR

'max number of clients reached' after days or weeks means connection accumulation: timeout set to 0 keeps idle connections open forever, or maxclients is too low for the pattern. Set an idle timeout (120 seconds or more) so stale clients are reaped, and size maxclients for your actual concurrency.

Fix

1. 'max number of clients reached' after days or weeks means connection accumulation: timeout set to 0 keeps idle connections open forever, or maxclients is too low for the pattern. Expected: You get the expected result; the problem is gone.

2. Set an idle timeout (120 seconds or more) so stale clients are reaped, and size maxclients for your actual concurrency. Expected: You get the expected result; the problem is gone.

3. Verify with CLIENT LIST and watch the connection count trend after the change. Expected: You see the expected output instead of the problem.

When to use

• You are setting up or using this Redis 'max number of clients reached' feature.
• The symptom matches: set a connection timeout.

When NOT to use

• Unrelated Redis 'max number of clients reached' issues (different feature, different failure).
• You need general documentation for the tool; check the official docs instead.

Compatibility

Reported against Redis 'max number of clients reached'. Source: https://github.com/classic298/docs/blob/HEAD/docs/tutorials/integrations/redis.md.

Variant phrasings

set a connection timeout

Why it happens

A Redis that runs fine for weeks then refuses connections is leaking clients.

Edge cases

• If your error message differs even slightly, this is probably a different issue; search the exact text.
• If the fix does not help, capture the full error output and check the source link for updates.

Source

https://github.com/classic298/docs/blob/HEAD/docs/tutorials/integrations/redis.md

Source: A Redis that runs fine for weeks then refuses connections is leaking clients.

Verified resolution: [Redis integration docs]: 'max number of clients reached' after days or weeks means connection accumulation: timeout set to 0 keeps idle connections open forever, or maxclients is too low for the pattern. Set an idle timeout (120 seconds or more) so stale clients are reaped, and size maxclients for your actual concurrency. Verify with CLIENT LIST and watch the connection count trend after the change.

Source URL: https://github.com/classic298/docs/blob/HEAD/docs/tutorials/integrations/redis.md

Not specified by the original author.

TL;DR: RESP connection timeouts almost always mean TLS is off or the port is blocked. Upstash requires TLS with no exceptions. Copy it from the console, do not retype it. Fix and verify Enable TLS, re-copy endpoint and port, and connect.

The fix

Diagnosing RESP connection timeouts to Upstash Redis

Symptom

The client hangs on connect, then times out. No auth error, no data URIs just silence.

Step 1: check TLS

Upstash requires TLS with no off switch. A plaintext connection attempt gets no useful error back, it just dies.

• ioredis: use the rediss:// scheme or pass tls in options.
• redis-py: pass ssl=True.
• redigo: redis.DialUseTLS(true).
• jedis: the boolean TLS flag in the constructor.
• redis-cli: redis-cli --tls.

Step 2: check the port and firewall

Use the port from the console TCP tab. Corporate firewalls and some VPC egress rules block non-HTTPS ports. If TLS is on and it still hangs, try from a different network to isolate firewall versus config.

Step 3: check DNS

The endpoint is a long regional hostname. A typo'd hostname hangs rather than erroring fast in some clients. Copy it from the console, do not retype it.

Fix and verify

Enable TLS, re-copy endpoint and port, and connect. A PONG on the first try confirms it. If your environment cannot do TLS on that port at all, switch to the REST API, which is plain HTTPS.

When to use this

• You are seeing this exact error message; match the block above, not just part of it.
• The failing call matches the scenario in the title: RESP timeouts to Upstash.
• You want the fastest verified fix before digging through logs.

When not to use this

• Your error text differs from the block above; close cousins often have different causes.
• The stack trace points at a different component than the one in the title.
• You already applied this fix and the error persists; look for a second cause instead of reapplying.

Compatibility

• Not pinned to a specific version; follows current RESP behavior.

Verified against Upstash connect-client docs: TLS is enabled by default for all databases and cannot be disabled; token is the password; per-client TLS examples (rediss scheme, ssl True, DialUseTLS, jedis true flag). Source: https://upstash.com/docs/redis/howto/connect-client

Not specified by the original author.

TL;DR

Add exponential backoff with jitter, cut page size and concurrency for this call, and resume from the last completed checkpoint instead of restarting the run. Start in the Redis instance metrics and the materialization job log, work on one affected item, and prove the fix there before running the full set. Most cases of this failure clear once the value named in step 2 is corrected at its source rather than retried.

redis API rate limit hit mid-online store validation error scan failed

Use this when

• You see this exact message or symptom in Redis online store: redis API rate limit hit mid-online store validation error scan failed
• One run, record, build, or object is affected and you can name it
• A retry without changing anything reproduces the same text

Not for this skill when

• Redis online store 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 in the Redis instance metrics and the materialization job log and search the log or history for the exact text in the block above, recording the time, the workspace or project, and the one object it names. Verify: you have one failing run or object identified, not a similar older failure
2. Inspect the Redis connection config in the online store block, the key prefix, and the TTL applied at write time, and check the retry settings, checkpoint record, and per item success log for this call. Verify: you can point to the specific value, field, or identity that does not match what this operation needs
3. Apply the fix at that source: add exponential backoff with jitter, cut page size and concurrency for this call, and resume from the last completed checkpoint instead of restarting the run. Verify: the corrected value or setting is visible in Redis online store itself, not only in a local config file
4. Re-run the original operation on the single affected item first: materialize one feature view for a short window, then read the written keys back before running the full window. Verify: that one item completes with no trace of the error text from the block above
5. Check the downstream result a user or the next job would see: a feature retrieval for one entity and a scan of recently written keys with their remaining TTL. Verify: the downstream result agrees with the source for the test item, in value and in timestamp
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 error and the changed setting, and no earlier item regressed

Variant phrasings

redis API rate limit hit mid-online store validation error scan failed

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

Redis online store version of this failure

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

Why does redis API rate limit hit mid-online store validation error scan failed 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 object state, not in the attempt.

Compatibility: Redis 7 or later as a Feast online store, TLS connection settings, Python redis client. The steps assume you can read the job or build log and change the named object in Redis online store.

Why it happens

In Redis online store, this failure usually means the caller kept sending at full pace after the service started refusing requests, so later items in the run were skipped or failed. The visible message is raised at the point where the bad state is consumed, which is rarely where it was created, so fixing the message text or retrying the last step changes nothing. Correcting the state at its source, then re-running one item and comparing the downstream result against the source, is what separates a real fix from a run that only looks successful.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_1li0lWKsqGSHuQDD6AZPXQ

Resolved from the public thread: https://vectle.com/posts/pst_1li0lWKsqGSHuQDD6AZPXQ

Thread query: redis API rate limit hit mid-online store validation error scan failed

TL;DR: Add exponential backoff with jitter, cut page size and concurrency for this call, and resume from the last completed checkpoint instead of restarting the run. Start in the Redis instance metrics and the materialization job log, work on one affected item, and prove the fix there before running the full set. Most cases of this failure clear once the value named in step 2 is corrected at its source rather than retried.