MySQL Data Migration Issue: Task Stuck on Startup with No Response

Note:
This topic has been translated from a Chinese forum by GPT and might contain errors.

Original topic: mysql 数据迁移问题,启动任务卡住,没有响应

| username: TiDBer_b1iRkG7I

The first image is not visible, so I can’t provide a translation for it. Here is the translation for the second image:

“TiDB is a distributed SQL database that features horizontal scalability, strong consistency, and high availability. It is compatible with the MySQL protocol and can be used as a drop-in replacement for MySQL. TiDB is designed to handle large-scale data and high-concurrency scenarios, making it suitable for various applications such as online transaction processing (OLTP), online analytical processing (OLAP), and hybrid transactional/analytical processing (HTAP).”

| username: TIDB-Learner | Original post link

Is the data volume large? Check the changes in system resource utilization.

| username: 路在何chu | Original post link

How long has it been stuck? What errors are reported in the logs?

| username: 有猫万事足 | Original post link

In this situation, you need to refer to the logs. Generally speaking, if the check-task involves many tables, it will take a relatively long time because it needs to compare the table structures of both upstream and downstream to complete the check.

| username: dba远航 | Original post link

Check the configuration file, I think it might be related to this.

| username: TiDBer_b1iRkG7I | Original post link

After it gets stuck and there is no response, where can I check the logs?

| username: kkpeter | Original post link

Check the logs of the dm-master or dm-worker components.

| username: 有猫万事足 | Original post link

There is a log folder in the installation directory of your DM master, which contains the logs of the DM master.

pwd
/tidb_dm/deploy/dm-master-8261/log

ll
total 28068
-rw------- 1 tidb tidb 28728512 Mar 1 17:33 dm-master.log
-rw-r–r-- 1 tidb tidb 4738 Dec 5 11:32 dm-master_stderr.log
-rw-r–r-- 1 tidb tidb 0 Jul 17 2023 dm-master_stdout.log

Similar to the above.

| username: TiDBer_b1iRkG7I | Original post link

This is the dm-master log:


This is the dm-worker log: no information output.

| username: TiDBer_b1iRkG7I | Original post link

This is the data source configuration file:

This is the task configuration file:

| username: TiDBer_b1iRkG7I | Original post link

It is most likely an issue caused by having too many tables. There are over 140 tables in the upstream and downstream databases. How long does this usually take? Is there any official documentation on this?

| username: IanWong | Original post link

I see that you are performing incremental synchronization. Does the downstream table exist?

| username: IanWong | Original post link

Having over a hundred tables shouldn’t be an issue. Could you provide the detailed logs?

| username: TiDBer_aaO4sU46 | Original post link

We also got stuck, how did you solve it later?

| username: 有猫万事足 | Original post link

You’re welcome to post a new thread to ask questions. It’s not recommended to consult under someone else’s question because each person’s issue might be different.

Also, try to provide logs, error messages, and similar information as much as possible.

| username: Jasper | Original post link

  1. How long exactly did it get stuck? Pay attention to the resource usage (memory, CPU, IO) of the node where DM is located.
  2. In the configuration, threads can control the concurrency of check-task. If the resource usage is not high, you can increase the concurrency and try again.