Table column type longtext is converted to AVRO bytes type but should be converted to bytes string type

[keweishang]

What did you do?

1. Create a table called employees. Its description column is enum.

CREATE TABLE employees (
  id int(20) unsigned NOT NULL AUTO_INCREMENT,
  description longtext COLLATE utf8mb4_general_ci NOT NULL,
  PRIMARY KEY (id)
);

2. Create TiCDC changefeed

tiup cdc cli changefeed create \
--pd="http://localhost:2379" \
--sink-uri="kafka://localhost:9092/test?protocol=avro&partition-num=1&replication-factor=3" \
--config=./configs/test.toml \
--opts "registry=http://localhost:8081" \
--changefeed-id=test

3. Insert a row

INSERT INTO employees values (1, 'test');

4. Check Kafka schema registry's schema.

...
{
    "name" : "description",
    "type" : [ "null", "bytes" ],
    "default" : null
  }
...

What did you expect to see?

The avro type of the description field should be string.

What did you see instead?

The avro type of the description field is bytes.

Versions of the cluster

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

Release Version: v5.3.0
Edition: Community
Git Commit Hash: 4a1b2e9fe5b5afb1068c56de47adb07098d768d6
Git Branch: heads/refs/tags/v5.3.0
UTC Build Time: 2021-11-24 13:31:41
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

TiCDC version (execute cdc version):

5.3.0

[keweishang]

In addition to longtext, text column type also has the same issue.

[zhangyangyu]

/remove-label affects-5.3