Re: permissions & foreign keys - Mailing list pgsql-general

From Jan Wieck
Subject Re: permissions & foreign keys
Date
Msg-id 200009041449.JAA02302@jupiter.jw.home
Whole thread Raw
In response to permissions & foreign keys  ("Tamsin" <tg_mail@bryncadfan.co.uk>)
Responses RE: permissions & foreign keys  ("Tamsin" <tg_mail@bryncadfan.co.uk>)
List pgsql-general
Tamsin wrote:
>
> I don't really see why it wants to update feedback_type?  Can anyone tell me
> what I'm doing wrong, or will I just have to grant update on feedback_type
> (and all other tables referenced by FKs)?
>

    It doesn't want to update it. It just does the SELECT ... FOR
    UPDATE to lock the now referenced row.  Doing  it  without  a
    lock  would  make  it  possible, that just after your backend
    checked that the PK row exists but before you got a chance to
    commit,  another  backend could delete that PK without seeing
    your just inserted reference. End  would  be  a  violated  FK
    constraint.

    The  bug  here is, that doing a SELECT ... FOR UPDATE already
    requires UPDATE permissions. The correct solution would be to
    require   a   REFERENCES  privilege  for  the  owner  of  the
    referencing table. But we don't have that up to now.

    Maybe I can do something about it for 7.1.


Jan

--

#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
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