Thread: A tidbit I spotted while playing in tablecmds.c

I think this is a bug:

postgres=# alter table only  x2 add if not exists i integer;
ERROR:  42701: column "i" of relation "x2" already exists

Note that it does not occur without the ONLY:

postgres=# alter table x2 add if not exists i integer;
NOTICE:  42701: column "i" of relation "x2" already exists, skipping
ALTER TABLE

And I think this would fix it:

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index eef3b3a26c..ad8c176793 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -4054,7 +4054,7 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab,
Relation rel,
  case AT_AddColumnToView: /* add column via CREATE OR REPLACE VIEW */
  address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
    false, false,
-   false, lockmode);
+   cmd->missing_ok, lockmode);
  break;
  case AT_AddColumnRecurse:
  address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,




-- 
greg

Hi,

On 2018-12-19 18:22:28 -0500, Greg Stark wrote:
> I think this is a bug:
> 
> postgres=# alter table only  x2 add if not exists i integer;
> ERROR:  42701: column "i" of relation "x2" already exists
> 
> Note that it does not occur without the ONLY:
> 
> postgres=# alter table x2 add if not exists i integer;
> NOTICE:  42701: column "i" of relation "x2" already exists, skipping
> ALTER TABLE
> 
> And I think this would fix it:
> 
> diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
> index eef3b3a26c..ad8c176793 100644
> --- a/src/backend/commands/tablecmds.c
> +++ b/src/backend/commands/tablecmds.c
> @@ -4054,7 +4054,7 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab,
> Relation rel,
>   case AT_AddColumnToView: /* add column via CREATE OR REPLACE VIEW */
>   address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
>     false, false,
> -   false, lockmode);
> +   cmd->missing_ok, lockmode);
>   break;
>   case AT_AddColumnRecurse:
>   address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,

Cursorily this seems right, but obviously need tests.

Greetings,

Andres Freund