On Mon, Nov 6, 2017 at 11:20 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Mon, Nov 6, 2017 at 3:51 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> This looks like it's on the right track to me. I hope Tom will look
>> into it, but if he doesn't I may try to get it committed myself.
>>
>> - if (rel->reloptkind == RELOPT_BASEREL)
>> - generate_gather_paths(root, rel);
>> + if (rel->reloptkind == RELOPT_BASEREL &&
>> + root->simple_rel_array_size > 2 &&
>> + !root->append_rel_list)
>>
>> This test doesn't look correct to me. Actually, it doesn't look
>> anywhere close to correct to me. So, one of us is very confused...
>> not sure whether it's you or me.
>>
> It is quite possible that I haven't got it right, but it shouldn't be
> completely bogus as it stands the regression tests and some manual
> verification. Can you explain what is your concern about this test?
Well, I suppose that test will fire for a baserel when the total
number of baserels is at least 3 and there's no inheritance involved.
But if there are 2 baserels, we're still not the topmost scan/join
target. Also, even if inheritance is used, we might still be the
topmost scan/join target.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
