Explain plan for UPDATE contains (NO DELETE)
What is the purpose of (NO DELETE) in line # 9?
This is an explain plan for an UPDATE query. I understand that in Vertica UPDATES, like DELETES, are a two-step process - a logical (soft) delete followed by a physical (hard) delete, so I'm not surprised to see DELETE referenced in the plan. I'm just not sure what it means in this context.
Many thanks for your help!
1 ------------------------------
2 QUERY PLAN DESCRIPTION:
3 ------------------------------
4
5 explain UPDATE my_schema.my_table set col_1 = val_1, etc....
6
7 Access Path:
8 +-DML UPDATE [Cost: 0, Rows: 0]
9 | Target Projection: my_schema.my_proj_name (NO DELETE)
10 | Target Prep:
11 | Execute on: All Nodes
12 | +---> JOIN HASH [Semi] [Cost: 76K, Rows: 977K] (PATH ID: 1) Inner (BROADCAST)
13 etc..