Fix INVALID_STREAM_TARGET error on COM_CDC_DUMP when restarting downstream subscription after kill

Environment

• Commit Hash: 62ecffc45ff824ca30ce64ffada7021438fedb1f
• Access Layer Version: 1.0.10-SNAPSHOT
• Is this an RD-provided temporary version? No / xxx temporary version (context unclear)

Description

When a downstream subscription is killed and then restarted, the COM_CDC_DUMP command reports an INVALID_STREAM_TARGET error.

Steps to Reproduce

1. Kill the downstream subscription process.
2. Attempt to restart the subscription.
3. The COM_CDC_DUMP command fails with the INVALID_STREAM_TARGET error.

Reproducibility: The original report indicates this is "必现/偶现/不确定/其他" (Consistent/Intermittent/Uncertain/Other). The specific selection is not provided.

Additional Context

• Test Changes: The report mentions "增加了xx测试场景/换了新机器/新跑了xx工具/替换新版本后才出的" (Added xx test scenario/changed machine/ran new tool/occurred after replacing version). The specific change is not detailed.
• Other Environment Anomalies/Changes: The report states "否/clog盘满过/手工做过。。/注入过xx异常" (No/CLOG disk was full/manually performed.../injected xx exception). The specific condition is not detailed.
• Log File: /data/1/cdc-example-runner/logs/11.log.out
• Machine Web Terminal: http://:24433/data/1/work_path/ob00.z1.obs0/ (Note: Host/IP is missing in the original URL)
• CDC Directory: /data/1/cdc_clusters/my_cdc_cluster/cdc_server1
• Connection String (for troubleshooting): mysql -h -P14881 (Note: Host is missing)

Logs/Screenshots

Two screenshots were included in the original report but cannot be rendered here. They are referenced by internal URLs.

Notes

This issue was reported from an external business perspective. The original form includes guidance on classifying such reports (e.g., Customer Feedback, Online Issue, Online Fault), but the specific classification for this case is not selected.

Start by examining the COM_CDC_DUMP handling and the downstream subscription restart path, then reproduce the failure using the reported restart steps. Inspect /data/1/cdc-example-runner/logs/11.log.out and the CDC directory for the invalid target state. Done means a killed downstream subscription can restart without INVALID_STREAM_TARGET.