read information_columns will produce cop request

[xiongjiwei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create view with subquery like create view as select * from t where t.a > (select max(a) from t)

select * from information_schema.columns will produce cop request

if we have many views, it will make tikv/tiflash increase CPU usage

problem introduce by #22363

2. What did you expect to see? (Required)

3. What did you see instead (Required)

4. What is your TiDB version? (Required)

[xiongjiwei]

same risk with show columns from table

[tangenta]

Related to #36426.

[tangenta]

I think an efficient solution for #22316 is to store the data type in the view when it is created.

OK. The data type should be calculated dynamically because the table can be altered.