Re: Declarative partitioning - another take

On Tue, Sep 27, 2016 at 2:46 PM, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> On 2016/09/27 15:44, Ashutosh Bapat wrote:
>>> By the way, I fixed one thinko in your patch as follows:
>>>
>>> - result->oids[i] = oids[mapping[i]];
>>> + result->oids[mapping[i]] = oids[i];
>>
>> While I can not spot any problem with this logic, when I make that
>> change and run partition_join testcase in my patch, it fails because
>> wrong partitions are matched for partition-wise join of list
>> partitions. In that patch, RelOptInfo of partitions are saved in
>> RelOptInfo of the parent by matching their OIDs. They are saved in the
>> same order as corresponding OIDs. Partition-wise join simply joins the
>> RelOptInfos at the same positions from both the parent RelOptInfos. I
>> can not spot an error in this logic too.
>
> OTOH, using the original logic makes tuple routing put tuples into the
> wrong partitions. When debugging why that was happening I discovered this
> and hence the proposed change.
>
> You mean that partition RelOptInfo's are placed using the canonical
> ordering of OIDs instead of catalog-scan-driven order, right? If that's
> true, then there is no possibility of wrong pairing happening, even with
> the new ordering of OIDs in the partition descriptor (ie, the ordering
> that would be produced by my proposed method above).

right! I don't know what's wrong, will debug my changes.

--
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company