Re: about truncate

Tom Lane wrote:
> Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
>
>> The SQL standard uses a recursive-by-default language. For example, the
>> rules for the DELETE command state:
>>
>
> Actually, I'm not convinced. Take a look at the SELECT WITH HIERARCHY
> OPTION stuff in SQL99 and later, in particular this from SQL99
> 12.2 <grant privilege statement>:
>
> 7) Let SWH be the set of privilege descriptors in CPD whose action
> is SELECT WITH HIERARCHY OPTION, and let ST be the set of
> subtables of O, then for every grantee G in SWH and for every
> table T in ST, the following <grant statement> is effectively
> executed without further Access Rule checking:
>
> GRANT SELECT ON T TO G GRANTED BY A
>
> It's difficult to read that any other way than that privileges are *not*
> auto-recursive, and they have chosen to spell "*" in GRANT as "WITH
> HIERARCHY OPTION" (gackk).
>
> On the other hand, it's hard to square that reading with the lack of any
> UPDATE or DELETE WITH HIERARCHY OPTION syntax. What am I missing here?
>
>
>

It's just occurred to me that if TRUNCATE no longer means TRUNCATE ONLY,
parallel restore will need to detect which server version is being used
so that for version > 8.3 it issues TRUNCATE ONLY. Otherwise there would
be a danger of a collision between a table and its children. The only
alternative would be to create a dependency between the data of a table
and the data of its children, which would be undesirable as well as more
complicated - in general the data should only depend on the table
creation (at most).

cheers

andrew