Re: PG_PAGE_LAYOUT_VERSION 5 - time for change

Gregory Stark napsal(a):
> Zdenek Kotala <Zdenek(dot)Kotala(at)Sun(dot)COM> writes:
>
>> 3) TOAST modification
>> a) TOAST table per attribute
>> b) replace chunk id with offset+variable chunk size
>> c) add column identification into first chunk
>>
>> Thats all. I think infomask/infomask2 shuffle flag should be done. TOAST
>> modification complicates in-place upgrade.
>
> I don't think TOAST table per attribute is feasible You would end up with
> thousands of toast tables. It might be interesting as an option if you plan to
> drop the column but I don't see it as terribly interesting.

Yeah, I could not remember what was a problem with this.

> What seemed to make sense to me for solving your problem was including the
> type oid in the toast chunks. I suppose attribute number might be just as good
> -- it would let you save upgrading chunks for dropped columns at the expense
> of having to look up the column info first.

It does not solve my problem now. Because I need it solve for old version of
PostgreSQL as well. But it should help in the future and also vacuum can easy
clean chunks related to dropped columns.

Zdenek

--
Zdenek Kotala Sun Microsystems
Prague, Czech Republic http://sun.com/postgresql