The Risks of Skipping DDL Operations in TiCDC

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Original topic: TiCDC跳过DDL操作的风险

| username: Daniel-W

[TiDB Usage Environment] Production Environment
[TiDB Version] V6.5.3
[Reproduction Path] What operations were performed when the issue occurred
[Encountered Issue: Issue Phenomenon and Impact]
I see that the official documentation mentions skipping DDL operations by adding 1 to the TSO. Could this operation be risky? In extreme scenarios, is it possible that more than just the DDL could be skipped?

TiCDC Fault Handling | PingCAP Documentation Center

| username: Soysauce520 | Original post link

What is the reason for the DDL failure? You can modify it on the standby database to allow TiCDC’s DDL to execute normally.

| username: Daniel-W | Original post link

There is a risk of data loss when skipping this DDL operation by incrementing the TSO by 1?

| username: Daniel-W | Original post link

The way to perform safe operations should be done like this:

| username: Fly-bird | Original post link

In extreme scenarios, it may skip non-DDL statements.

| username: 路在何chu | Original post link

You can skip it. There’s no risk, just skip over it.

| username: tidb菜鸟一只 | Original post link

Are you suspecting that the skipped TSO corresponds to other statements besides DDL statements? This shouldn’t be the case. A TSO should correspond to a single transaction, and there shouldn’t be other statements sharing a TSO with a DDL statement.

| username: Daniel-W | Original post link

Could you please elaborate?

| username: Daniel-W | Original post link

Yes, that’s right. There won’t be any issues this way.

| username: zhanggame1 | Original post link

In the database, there can only be one transaction per TSO, so concurrent transactions are not possible.

| username: Daniel-W | Original post link

Got it. Thanks for the guidance, everyone!

| username: heiwandou | Original post link

Manually execute this transaction, then skip it.

| username: oceanzhang | Original post link

Manual execution

| username: system | Original post link

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