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

On 2017/09/04 21:32, Ashutosh Bapat wrote:
> On Mon, Sep 4, 2017 at 10:04 AM, Amit Langote
>> By the way, if you want to get rid of PartitionedChildRelInfo, you can do
>> that as long as you find some other way of putting together the
>> partitioned_rels list to add into the ModifyTable (Append/MergeAppend)
>> node created for the root partitioned table.  Currently,
>> PartitionedChildRelInfo (and the root->pcinfo_list) is the way for
>> expand_inherited_rtentry() to pass that information to the planner's
>> path-generating code.  We may be able to generate that list when actually
>> creating the path using set_append_rel_pathlist() or
>> inheritance_planner(), without having created a PartitionedChildRelInfo
>> node beforehand.
> 
> AFAIU, the list contained RTIs of the relations, which didnt' have
> corresponding AppendRelInfos to lock those relations. Now that we
> create AppendRelInfos even for partitioned partitions, I don't think
> we need the list to take care of the locks.
I don't think so either.  (Since I haven't followed discussions on this 
thread in detail yet, I don't understand the idea/need of creating 
AppendRelInfos for partitioned partitions, though.)

>>> Though I haven't read the patch yet, I think the above code is useless.
>>> And I proposed a patch to clean it up before [1].  I'll add that patch to
>>> the next commitfest.
>>
>> +1.
> +1. Will Fujita-san's patch also handle getting rid of partitioned_rels list?

No.  The patch just removes the partitioned_rels list from 
nodeModifyTable.c.

Best regards,
Etsuro Fujita