Some data may be replicated to downstream if table becomes ineligible after DDL

[amyangfei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do? If possible, provide a recipe for reproducing the error.

2. setup a cdc cluster, and start a changefeed

3. in upstream, execute create table t2 (id int primary key);insert into t2 values (1),(2);, everything is normal

4. in upstream, execute alter table t2 drop primary key; insert into t2 values (3),(4);

5. What did you expect to see?

The replication of table t2 will be paused and no more data is replicated

3. What did you see instead?

t> select * from t2;
+----+
| id |
+----+
| 1  |
| 2  |
| 3  |
| 4  |
+----+
4 rows in set

> show create table t2;
+-------+-------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                |
+-------+-------------------------------------------------------------------------------------------------------------+
| t2    | CREATE TABLE `t2` (\n  `id` int(11) NOT NULL,\n  PRIMARY KEY (`id`)\n) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+-------------------------------------------------------------------------------------------------------------+
1 row in set

4. Versions of the cluster

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

     Release Version: v4.0.0
     

   • TiCDC version (execute cdc version):

     Release Version: v4.0.2-32-ga3d9c7e
     Git Commit Hash: a3d9c7e5cc35ef57afa338f74edeea80ae4dbd59
     Git Branch: master
     UTC Build Time: 2020-07-14 08:00:04
     Go Version: go version go1.14.4 linux/amd64