Re: about truncate

Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.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