Is it abnormal to modify the target table structure during DM synchronization?

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

Original topic: dm同步 target表结构修改是否异常

| username: TiDBer_TxSpaZ25

[TiDB Usage Environment] Production Environment / Testing / PoC
[TiDB Version]
[Reproduction Path] Is there any abnormality when modifying the target table structure in DM synchronization?
If I change the target table structure from varchar to bigint, will it affect DM, and what consequences might it bring?

| username: Jellybean | Original post link

First, DM supports synchronization with inconsistent upstream and downstream table structures.

If the downstream table structure is changed to bigint, and the varchar you insert is an integer, it should be able to be inserted; otherwise, it will fail.
It is recommended that you fully verify in a test environment first, simulate various synchronization scenarios according to your own business, and confirm that there are no issues before using it.

| username: dba远航 | Original post link

DM supports heterogeneous tables, so inserting numerical data should not be a problem.

| username: 有猫万事足 | Original post link

Assuming you did not filter the alter table event, this should not have any impact. The alter table can also be executed when synchronized to the downstream. There should not be any type inconsistency issues.

| username: andone | Original post link

DM supports source and target table structure inconsistency.