Re: Partition-wise join for join between (declaratively) partitioned tables

On Wed, Mar 22, 2017 at 3:19 PM, Ashutosh Bapat
<ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
>>>>
>> In an attempt to test the geqo side of this patch, I reduced
>> geqo_threshold to 6 and set enable_partitionwise_join to to true and
>> tried following query, which crashed,
>>
>> explain select * from prt, prt2, prt3, prt32, prt4, prt42 where prt.a
>> = prt2.b and prt3.a = prt32.b and prt4.a = prt42.b and prt2.a > 1000
>> order by prt.a desc;
>>
>> Stack-trace for the crash is as follows,
>>
> Nice catch. When reparameterize_path_by_child() may be running in a
> temporary memory context while running in GEQO mode. It may add a new
> PPI to base relation all in the temporary context. In the next GEQO
> cycle, the ppilist will be clobbered since the temporary context is
> reset for each geqo cycle. The fix is to allocate PPI in the same
> memory context as the RelOptInfo similar to mark_dummy_rel().
>
> I also found another problem. In geqo, we never call
> generate_partition_wise_join_paths() which set cheapest paths for each
> child-join. Because of this cheapest_*_paths are never set for those
> rels, thus segfaulting in functions like sort_inner_and_outer() which
> use those.
>
> Here's patch fixing both the issues. Please let me know if it fixes
> the issues you are seeing.

I tested the applied patch, it is fixing the reported issue.

--
Regards,
Rafia Sabih
EnterpriseDB: http://www.enterprisedb.com/