Re: Inheritance: Performance & Indexes

On 18 Jun 2001, Itai Zukerman wrote:

> Just curious:
>
> create table a (x int4 primary key);
> create table a1 () inherits (a);
>
> [...]
>
> delete from a where x = 1000;
>
> I take it that this is equivalent to:
>
> delete from only a where x = 1000;
> delete from only a1 where x = 1000;
>
Yes.

> In particular, for performance reasons I should try to limit the
> delete to a1 wherever possible?
Well, you should be aware what'll actually happen when you do
updates/deletes on parent table. If you mean to delete only from parent,
use 'only'.

> Also, it looks like a1 doesn't inherit the primary key index. Is that
> intentional or a bug?
Its a problem of current implementation (aka bug)
>
> Finally, is it possible to specify that x values be unique across
> both a *and* a1, without triggers?
Not currently, but there are talks about revamping of inheritance system,
see archives

-alex