TiKV-CDC Memory Quota Reached 512 MB After TiCDC Restart, Changefeed Stuck and Unrecoverable

[wlwilliamx]

What did you do?

1. One CDC instance running in Kubernetes was restarted.
2. After the restart, the memory usage of TiKV-CDC began to increase continuously.
3. Eventually, the memory quota (512 MB) was fully utilized, causing the Changefeed to hang.
4. Restarting the CDC instance multiple times did not resolve the issue. The memory quota of TiKV-CDC remained at 512 MB, and the Changefeed remained stuck.

What did you expect to see?

• TiKV-CDC should release memory after the restart and operate within the configured memory quota.
• The Changefeed should resume normal processing after restarting the CDC instance.

What did you see instead?

• TiKV-CDC's memory usage continued to increase after the restart and eventually hit the 512 MB quota.
• The Changefeed was stuck and unable to recover.
• Restarting the CDC instance multiple times did not free up memory or resolve the issue. The memory quota of TiKV-CDC remained at 512 MB.

Versions of the cluster

Upstream TiKV version (execute tikv-server --version):

v7.5.4, with 14 TiKV nodes

TiCDC version (execute cdc version):

v7.5.4, with 2 TiCDC nodes

[wlwilliamx]

Report this bug in TiKV #18169