Describe the issue
I have ReplicatedReplacingMergeTree on one shard and two replicas managed by ZooKeeper all running on a Kubernetes cluster managed by clickhouse-operator. The setup works fine, data is being replicated correctly but the Prometheus metrics report several ZooKeeperUserExceptions. ClickHouse is not logging those exception, not even on trace level so i have no chance on seeing what the issues are about.

How to reproduce

• ClickHouse server version 21.1.2
• ZooKeeper 3.6.1
• CREATE TABLE with ReplicatedReplacingMergeTree as engine
• Set logger level to Trace

<logger>
    <level>trace</level>
    <log>/var/log/clickhouse-server/clickhouse-server.log</log>
    <errorlog>/var/log/clickhouse-server/clickhouse-server.err.log</errorlog>
    <size>1000M</size>
    <count>10</count>
</logger>

• Grep logs for anything which might be related to the error messages, e.g.

 grep -i -E "No node|Bad version|No children for ephemerals|Node exists|Not empty" -r /var/log/clickhouse-server/

• No information on how to reproduce as i can't see the root cause in the missing logs.

Expected behavior
If Prometheus metrics are reporting ZooKeeperUserExceptions i want to see them also in the logs. It seems they are not fatal errors, but normally i would expect them to see on logger level Error already, otherwise Debug at least Trace.

Error message and/or stacktrace
No stacktrace as i can't see the exceptions in the missing logs.

Additional context
I first thought its related to the ClickHouse Kubernetes operator so i opened a ticket there with additional details but we found out its rather a ClickHouse logger issue.

When looking at the implementation you can find the profile events increment here

The places using Coordination::isUserError(Error code) are not really logging anything beside one LOG_INFO in a specific condition

I would expect more logs in that context or the correctly thrown Exceptions being logged where catched.