Why shardingsphere select before insert to DB

[vuhoanghiep1993]

When I have 3 datasource and allow sql log, I see:

Logic SQL: select oe1_0.order_id,oe1_0.location,oe1_0.status,oe1_0.user_id from t_order oe1_0 where oe1_0.order_id=? 
09:09:15.490 [http-nio-8972-exec-4] INFO  ShardingSphere-SQL - 

Actual SQL: db0 ::: select oe1_0.order_id,oe1_0.location,oe1_0.status,oe1_0.user_id from T_ORDER oe1_0 where oe1_0.order_id=? ::: [1] 
09:09:15.490 [http-nio-8972-exec-4] INFO  ShardingSphere-SQL - 

Actual SQL: db1 ::: select oe1_0.order_id,oe1_0.location,oe1_0.status,oe1_0.user_id from T_ORDER oe1_0 where oe1_0.order_id=? ::: [1] 
09:09:15.490 [http-nio-8972-exec-4] INFO  ShardingSphere-SQL - 

Actual SQL: db2 ::: select oe1_0.order_id,oe1_0.location,oe1_0.status,oe1_0.user_id from T_ORDER oe1_0 where oe1_0.order_id=? ::: [1] 
09:09:16.801 [http-nio-8972-exec-4] INFO  ShardingSphere-SQL - 

Logic SQL: insert into t_order (location,status,user_id,order_id) values (?,?,?,?) 

I have a question why shardingsphere need select before insert? can I disable this because select will increase request to DB if have more dataresource?

I think if query go through all table cause performance waste , can we improve it ?

2. I have sharing by "location" column but ID is "order_id" column, when I select by order_id, it will select all physical table ? can shardingshere get it exactly physical table