Latency increased during tidb cluster rolling upgrade

[tennix]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

This is not yet reproduced.

TiDB cluster is deployed in k8s, the original procedure is changing the log level of pd/tikv/tidb configuration, and tidb-operator will roll upgrade the whole cluster.

2. What did you expect to see? (Required)

Low latency during rolling upgrade

3. What did you see instead (Required)

A latency spike appeared during TiKV rolling upgrade.


The application latency also increased to 13s.

Though the TiKV leader from the Grafana did not drop to zero during tikv upgrade. It did drop to zero from PD's monitoring

4. What is your TiDB version? (Required)

v4.0.9

[zyguan]

No update for a long time, feel free to reopen it if the issue still exists.

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.