Write conflict happened while upgrade dm V2.0.1 to nightly

[XuJianxu]

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.
   200 upstream mysql, 200* dm worker, 3*dm master, 200K QPS+TPS in upstream.
   Upgrade dm cluster from 2.0.1 to nightly。

2. What did you expect to see?
   no write conflict

3. What did you see instead?
   write conflict happened
   

4. Versions of the cluster

   • DM version (run dmctl -V or dm-worker -V or dm-master -V):

     v2.0.1
     

   • Upstream MySQL/MariaDB server version:

     mysql5.6/5.7
     

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

     4.0.10
     

   • How did you deploy DM: DM-Ansible or manually?

     DM-Ansible
     

   • Other interesting information (system version, hardware config, etc):

5. current status of DM cluster (execute query-status in dmctl)

6. Operation logs

   • Please upload dm-worker.log for every DM-worker instance if possible
   • Please upload dm-master.log if possible
   • Other interesting logs
   • Output of dmctl's commands with problems

7. Configuration of the cluster and the task

   • dm-worker.toml for every DM-worker instance if possible
   • dm-master.toml for DM-master if possible
   • task config, like task.yaml if possible
   • inventory.ini if deployed by DM-Ansible

8. Screenshot/exported-PDF of Grafana dashboard or metrics' graph in Prometheus for DM if possible

[lance6716]

write conflict may caused by #1895 (comment). since the write conflict still occurs at this moment, I'll try to adjust the table structure by operate-schema and see if the conflict is still here

[lance6716]

after setting correct table schema for every shard tables, this problem doesn't happen again.