Re: [PATCH] Largeobject access controls

Itagaki Takahiro wrote:
> KaiGai Kohei <kaigai@ak.jp.nec.com> wrote:
> 
>> The pg_largeobject system catalog is reworked to manage its metadata.
>>
>>   CATALOG(pg_largeobject,2613)
>>   {
>>       Oid         loowner;        /* OID of the owner */
>>       Oid         lochunk;        /* OID of the data chunks */
>>       aclitem     loacl[1];       /* access permissions */
>>   } FormData_pg_largeobject;
>>
>> Actual data chunks are stored in the toast relation of pg_largeobject,
>> and its chunk_id is stored in the pg_largeobject.lochunk.
> 
> A bit acrobatic, but insteresting idea.
> 
> I have some random comments:
> 
>   * Do you measure performance of the new LO implementation?
>     AFAIK, Users expect performance benefits to LO; TOASTed
>     bytea slows down when the size of data is 100KB or greater
>     even if they don't use random seeks.

Not yet. Can you recommend commonly-used workload?

>   * We might take care of DROP ROLE and REASSIGN/DROP OWNED.
>     Or, we might have large object without owner.
>     It might require full-scanning of pg_largeobject table,
>     but we can accept it because the size of pg_largeobject
>     will be smaller; we have actual data out of the table.

I think it should be implemented using the dependency mechanism.
It requires full-scanning on the pg_shdepend tables, but it has
been accepted.

>   * Don't we also need "ALTER LARGE OBJECT <oid> OWNER TO <user>"
>     for consistency?

Agreed. It will be also necessary to implement REASSIGN OWNED.

Thanks,
-- 
OSS Platform Development Division, NEC
KaiGai Kohei <kaigai@ak.jp.nec.com>