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

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