Re: Error with DEFAULT VALUE in temp table - Mailing list pgsql-hackers

Hi, Tom!

Thank you for working on this. I see you've fixed the patch and 
committed it as a0b99fc1220. I tested it a bit and see some side effects 
which may be unintentional.

1. SCHEMA lost object_name.

Before:

     postgres=# create schema foo;
     CREATE SCHEMA
     postgres=# drop schema foo;
     DROP SCHEMA
     postgres=# select * from dropped_objects \gx
     -[ RECORD 1 ]---+-------
     n               | 1
     classid         | 2615
     objid           | 16404
     objsubid        | 0
     original        | t
     normal          | f
     is_temporary    | f
     object_type     | schema
     schema_name     |
     object_name     | foo
     object_identity | foo
     address_names   | {foo}
     address_args    | {}

After:

     postgres=# select * from dropped_objects \gx
     -[ RECORD 1 ]---+-------
     n               | 1
     classid         | 2615
     objid           | 16394
     objsubid        | 0
     original        | t
     normal          | f
     is_temporary    | f
     object_type     | schema
     schema_name     |
     object_name     |
     object_identity | foo
     address_names   | {foo}
     address_args    | {}


2. DEFAULT VALUE now has schema_name and object_name.

Before:

     postgres=# create temp table bar (a int default 0);
     CREATE TABLE
     postgres=# drop table bar;
     DROP TABLE
     postgres=# select * from dropped_objects where object_type = 
'default value' \gx
     -[ RECORD 1 ]---+------------------
     n               | 4
     classid         | 2604
     objid           | 16422
     objsubid        | 0
     original        | f
     normal          | f
     is_temporary    | f
     object_type     | default value
     schema_name     |
     object_name     |
     object_identity | for pg_temp.bar.a
     address_names   | {pg_temp,bar,a}
     address_args    | {}

After:

     postgres=# select * from dropped_objects where object_type = 
'default value' \gx
     -[ RECORD 1 ]---+------------------
     n               | 4
     classid         | 2604
     objid           | 16430
     objsubid        | 0
     original        | f
     normal          | f
     is_temporary    | t
     object_type     | default value
     schema_name     | pg_temp
     object_name     | bar
     object_identity | for pg_temp.bar.a
     address_names   | {pg_temp,bar,a}
     address_args    | {}

This may be intentional, but doesn't quite match the description for 
object_name in the docs:

     Name of the object, if the combination of schema and name can be 
used as a unique identifier for the object; otherwise NULL.

Also it doesn't match with the record for the column itself:

     postgres=# create temp table bar (a int default 0);
     CREATE TABLE
     postgres=# alter table bar drop column a;
     ALTER TABLE
     postgres=# select * from dropped_objects \gx
     -[ RECORD 1 ]---+------------------
     n               | 1
     classid         | 1259
     objid           | 16435
     objsubid        | 1
     original        | t
     normal          | f
     is_temporary    | t
     object_type     | table column
     schema_name     | pg_temp
     object_name     |
     object_identity | pg_temp.bar.a
     address_names   | {pg_temp,bar,a}
     address_args    | {}
     -[ RECORD 2 ]---+------------------
     n               | 2
     classid         | 2604
     objid           | 16438
     objsubid        | 0
     original        | f
     normal          | f
     is_temporary    | t
     object_type     | default value
     schema_name     | pg_temp
     object_name     | bar
     object_identity | for pg_temp.bar.a
     address_names   | {pg_temp,bar,a}
     address_args    | {}

object_name is null for the table column, but not null for its default 
value.

As for schema_name, I'm not sure whether it should be null or not. 
Currently schema_name is null for triggers and policy objects, but that 
may be accidental.

Best regards,

-- 
Sergey Shinderuk        https://postgrespro.com/