Horton

Re: Declarative partitioning - another take

Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>

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From: Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>
To: pgsql-hackers@postgresql.org
Date: 2017-05-10T10:50:38Z
Lists: pgsql-hackers 
On 2016/11/18 1:43, Robert Haas wrote:
> On Thu, Nov 17, 2016 at 6:27 AM, Amit Langote
> <Langote_Amit_f8@lab.ntt.co.jp> wrote:

>>> - The code in make_modifytable() to swap out the rte_array for a fake
>>> one looks like an unacceptable kludge.  I don't know offhand what a
>>> better design would look like, but what you've got is really ugly.

>> Agree that it looks horrible.  The problem is we don't add partition
>> (child table) RTEs when planning an insert on the parent and FDW
>> partitions can't do without some planner handling - planForeignModify()
>> expects a valid PlannerInfo for deparsing target lists (basically, to be
>> able to use planner_rt_fetch()).

> If it's only needed for foreign tables, how about for v1 we just throw
> an error and say errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> errmsg("cannot route inserted tuples to a foreign table") for now.  We
> can come back and fix it later.  Doing more inheritance expansion

> Coming up with some new FDW API or some modification
> to the existing one is probably better, but I don't really want to get
> hung up on that right now.

I started working on this.  I agree that the changes made in 
make_modifytable would be unacceptable, but I'd vote for Amit's idea of 
passing a modified PlannerInfo to PlanForeignModify so that the FDW can 
do query planning for INSERT into a foreign partition in the same way as 
for INSERT into a non-partition foreign table.  (Though, I think we 
should generate a more-valid-looking working-copy of the PlannerInfo 
which has Query with the foreign partition as target.)  I'm not sure 
it's a good idea to add a new FDW API or modify the existing one such as 
PlanForeignModify for this purpose.

Best regards,
Etsuro Fujita

Commits

  1. Fix typo.

  2. Document trigger-firing behavior for inheritance/partitioning.

  3. Fire per-statement triggers on partitioned tables.

  4. Set ecxt_scantuple correctly for tuple routing.

  5. Fix interaction of partitioned tables with BulkInsertState.

  6. Avoid core dump for empty prepared statement in an aborted transaction.

  7. Fix some problems in check_new_partition_bound().

  8. Remove unnecessary arguments from partitioning functions.

  9. Fix reporting of constraint violations for table partitioning.

  10. Fix tuple routing in cases where tuple descriptors don't match.

  11. Invalid parent's relcache after CREATE TABLE .. PARTITION OF.

  12. Doc: improve documentation about inheritance.