How to view the progress of the current DDL job?

You can use ADMIN SHOW DDL to view the progress of the current DDL job. The operation is as follows:

*************************** 1. row ***************************
       OWNER: 1a1c4174-0fcd-4ba0-add9-12d08c4077dc
RUNNING_JOBS: ID:121, Type:add index, State:running, SchemaState:write reorganization, SchemaID:1, TableID:118, RowCount:77312, ArgLen:0, start time: 2018-12-05 16:26:10.652 +0800 CST, Err:<nil>, ErrCount:0, SnapshotVersion:404749908941733890
     SELF_ID: 1a1c4174-0fcd-4ba0-add9-12d08c4077dc

From the above results, you can get that the ADD INDEX operation is currently being processed. You can also get from the RowCount field of the RUNNING_JOBS column that now the ADD INDEX operation has added 77312 rows of indexes.