Adding an index may result in increased lag when the timeout is large

[wk989898]

Is your feature request related to a problem?

pingcap/tiflow#12454

Describe the feature you'd like

When the user sets a large timeout, for the add index ddl, try to use other timeout parameters to avoid a long execution time that would cause the lag increase

Describe alternatives you've considered

This will add a mysql connection

Teachability, Documentation, Adoption, Migration Strategy

No response