On 2018/11/06 4:37, Alvaro Herrera wrote:
> On 2018-Nov-02, Amit Langote wrote:
>
>> Well, performDeletion *does* drop the child, because when the parent is
>> dropped due to its ON COMMIT DROP action, it's done using:
>>
>> /*
>> * Since this is an automatic drop, rather than one
>> * directly initiated by the user, we pass the
>> * PERFORM_DELETION_INTERNAL flag.
>> */
>> performDeletion(&object,
>> DROP_CASCADE, PERFORM_DELETION_INTERNAL);
>>
>> Note the DROP_CASCADE, which means its children will be deleted as part of
>> this.
>
> I think this code should collect all the OIDs to be dropped, then use a
> single performMultipleDeletions() at the end, after the heap_truncate
> call is done. That seems better to me than a relkind check.
I've posted in a new thread about this:
* ON COMMIT actions and inheritance *
https://www.postgresql.org/message-id/68f17907-ec98-1192-f99f-8011400517f5%40lab.ntt.co.jp
I've to say that what you suggest seems to be a more elegant way to fix
this issue. My patch fixes it by reconstructing the oids_to_truncate list
by removing the OIDs of children that were dropped via the ON COMMIT DROP
action of the parent using a SearchSysCacheExists1 test.
Thanks,
Amit