insert returning panic when returning implicit padded NULL values

[broccoliSpicy]

Describe the bug

perhaps we shouldn't punt the NULL padding logic to the batch executor.

To Reproduce

dev=> create table t (v1 int, v2 real);
CREATE_TABLE
dev=> insert into t (v2) values (1) returning *;
SSL SYSCALL error: EOF detected
The connection to the server was lost. Attempting reset: Failed.

Expected behavior

postgres=# create table t1 (v1 int, v2 real);
CREATE TABLE
postgres=# insert into t1 (v2) values (1) returning *;
 v1 | v2 
----+----
    |  1
(1 row)

INSERT 0 1
postgres=# 

Additional context

No response

[broccoliSpicy]

@BugenZhao @Eurekaaw PTAL

[broccoliSpicy]

I think revert the NULL padding punt we did earlier is the easiest way to fix this.

NULL padding punt PR

[y-wei]

I'd suggest the problem is:

risingwave/src/frontend/src/optimizer/plan_node/logical_insert.rs

Lines 65 to 67 in 2e789bd

	let schema = if returning {
	input.schema().clone()
	} else {

The schema shall be the source's schema plus padding columns. Afterwards in insert executor a datachunk shall be yielded after evaluating default columns;

postgres=# create table td (v1 int default 1, v2 int);
CREATE TABLE
postgres=# insert into td (v2) values (0) returning *;
 v1 | v2 
----+----
  1 |  0
(1 row)

[broccoliSpicy]

just out of curiosity, do we have a design to handle create table td (v1 int default 1, v2 int); ?

in the case of create table t( a int, b timestamp default current_timestamp);, we may want to evaluate the function as soon as the prompt arrives, I suppose?
so we need to handle it in the frontend?
in a distributed system like risingwave, there might be some inconsistency if we evaluate the function current_timestamp in create table t( a int, b timestamp default current_timestamp) in the batch executor.

[y-wei]

just out of curiosity, do we have a design to handle create table td (v1 int default 1, v2 int); ?

Yes! See #8999

[broccoliSpicy]

this is not very kind of you ...

[github-actions]

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