Re: [HACKERS] UPDATE of partition key

On 24 November 2017 at 10:52, Amit Langote
<Langote_Amit_f8@lab.ntt.co.jp> wrote:
> On 2017/11/23 21:57, Amit Khandekar wrote:
>> If we collect the partition keys in expand_partitioned_rtentry(), we
>> need to pass the root relation also, so that we can convert the
>> partition key attributes to root rel descriptor. And the other thing
>> is, may be, we can check beforehand (in expand_inherited_rtentry)
>> whether the rootrte's updatedCols is empty, which I think implies that
>> it's not an UPDATE operation. If yes, we can just skip collecting the
>> partition keys.
>
> Yeah, it seems like a good idea after all to check in
> expand_inherited_rtentry() whether the root RTE's updatedCols is non-empty
> and if so check if any of the updatedCols are partition keys.  If we find
> some, then it will suffice to just set a simple flag in the
> PartitionedChildRelInfo that will be created for the root table.  That
> should be done *after* we have visited all the tables in the partition
> tree including some that might be partitioned and hence will provide their
> partition keys.  The following block in expand_inherited_rtentry() looks
> like a good spot:
>
>         if (rte->inh && partitioned_child_rels != NIL)
>         {
>             PartitionedChildRelInfo *pcinfo;
>
>             pcinfo = makeNode(PartitionedChildRelInfo);

Yes, I am thinking about something like that. Thanks.

I am also working on your suggestion of moving the
convert-to-root-descriptor logic from ExecInsert() to ExecUpdate().

So, in the upcoming patch version, I am intending to include the above
two, and if possible, Robert's idea of re-using is_partition_attr()
for pull_child_partition_columns().


-- 
Thanks,
-Amit Khandekar
EnterpriseDB Corporation
The Postgres Database Company