Table sink can never release memory quota when sink factory fails

[hicqu]

What did you do?

1. create a cdc cluster and cdc changefeed;
2. make the downstream sink block, wait for memory quota gets full;
3. inject an error to the downstream sink;
4. recover the downstream sink.

What did you expect to see?

Table sinks can be re-created successfully.

What did you see instead?

Table sinks can never be re-created successfully. And memory quota is always full.

Versions of the cluster

Upstream TiDB cluster version (execute SELECT tidb_version(); in a MySQL client):

(paste TiDB cluster version here)

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

(paste TiKV version here)

TiCDC version (execute cdc version):

(paste TiCDC version here)