Re: [PATCH] Infinite loop while acquiring new TOAST Oid

Hi hackers!

Any suggestions on the previous message (64-bit toast value ID with
individual counters)?

On Tue, Dec 13, 2022 at 1:41 PM Nikita Malakhov <hukutoc(at)gmail(dot)com> wrote:

> Hi hackers!
>
> I've prepared a patch with a 64-bit TOAST Value ID. It is a kind of
> prototype
> and needs some further work, but it is already working and ready to play
> with.
>
> I've introduced 64-bit value ID field in varatt_external, but to keep it
> compatible
> with older bases 64-bit value is stored as a structure of two 32-bit
> fields and value
> ID moved to be the last in the varatt_external structure. Also, I've
> introduced
> different ID assignment function - instead of using global OID assignment
> function
> I use individual counters for each TOAST table, automatically cached and
> after
> server restart when new value is inserted into TOAST table maximum used
> value
> is searched and used to assign the next one.
>
> >Andres Freund:
> >I think we'll need to do something about the width of varatt_external to
> make
> >the conversion to 64bit toast oids viable - and if we do, I don't think
> >there's a decent argument for staying with 4 byte toast OIDs. I think the
> >varatt_external equivalent would end up being smaller in just about all
> cases.
> >And as you said earlier, the increased overhead inside the toast table /
> index
> >is not relevant compared to the size of toasted datums.
>
> There is some small overhead due to indexing 64-bit values. Also, for
> smaller
> tables we can use 32-bit ID instead of 64-bit, but then we would have a
> problem
> when we reach the limit of 2^32.
>
> Pg_upgrade seems to be not a very difficult case if we go keeping old TOAST
> tables using 32-bit values,
>
> Please have a look. I'd be grateful for some further directions.
>
> GIT branch with this feature, rebased onto current master:
> https://github.com/postgrespro/postgres/tree/toast_64bit
>
>
> --
Regards,
Nikita Malakhov
Postgres Professional
https://postgrespro.ru/