operate-schema set --flush may cause dm-worker server to restart

[glkappe]

dm version：v2.0.3

operate-schema set --flush may cause dm-worker server to restart，This is an abnormal restart

dm-worker log：
｛Because the operate-schema set --flush operation is executed multiple times, there are many restarts, and only the screenshot information of the restart is shown here.｝

std error
stderr.txt

[GMHDBJD]

#1724 (comment) It's a bug if we use --flush to create a table structure for fresh new tables

[glkappe]

How to understand the definition of the new table, currently dm task is in sync state

[GMHDBJD]

Syncer meet the table for the first time(no checkpoint for that table before)

[lance6716]

closed by #1799