Horton

Re: UPDATE of partition key

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Amit Khandekar <amitdkhan.pg@gmail.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Robert Haas <robertmhaas@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-06-30T21:45:51Z
Lists: pgsql-hackers 
On Fri, Jun 30, 2017 at 12:01 AM, Amit Khandekar <amitdkhan.pg@gmail.com> wrote:
> On 29 June 2017 at 07:42, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> wrote:
>> Hi Amit,
>>
>> On 2017/06/28 20:43, Amit Khandekar wrote:
>>> In attached patch v12
>>
>> The patch no longer applies and fails to compile after the following
>> commit was made yesterday:
>>
>> commit 501ed02cf6f4f60c3357775eb07578aebc912d3a
>> Author: Andrew Gierth <rhodiumtoad@postgresql.org>
>> Date:   Wed Jun 28 18:55:03 2017 +0100
>>
>>     Fix transition tables for partition/inheritance.
>
> Thanks for informing Amit.
>
> As Thomas mentioned upthread, the above commit already uses a tuple
> conversion mapping from leaf partition to root partitioned table
> (mt_transition_tupconv_maps), which serves the same purpose as that of
> the mapping used in the update-partition-key patch during update tuple
> routing (mt_resultrel_maps).
>
> We need to try to merge these two into a general-purpose mapping array
> such as mt_leaf_root_maps. I haven't done that in the rebased patch
> (attached), so currently it has both these mapping fields.
>
> For transition tables, this map is per-leaf-partition in case of
> inserts, whereas it is per-subplan result rel for updates. For
> update-tuple routing, the mapping is required to be per-subplan. Now,
> for update-row-movement in presence of transition tables, we would
> require both per-subplan mapping as well as per-leaf-partition
> mapping, which can't be done if we have a single mapping field, unless
> we have some way to identify which of the per-leaf partition mapping
> elements belong to per-subplan rels.
>
> So, it's not immediately possible to merge them.

Would make sense to have a set of functions with names like
GetConvertor{From,To}{Subplan,Leaf}(mtstate, index) which build arrays
m_convertors_{from,to}_by_{subplan,leaf} the first time they need
them?

-- 
Thomas Munro
http://www.enterprisedb.com

Commits

  1. Avoid referencing off the end of subplan_partition_offsets.

  2. Allow UPDATE to move rows between partitions.

  3. Remove useless lookup of root partitioned rel in ExecInitModifyTable().

  4. Factor error generation out of ExecPartitionCheck.

  5. Minor preparatory refactoring for UPDATE row movement.

  6. Simplify and encapsulate tuple routing support code.

  7. Avoid coercing a whole-row variable that is already coerced.

  8. Use ResultRelInfo ** rather than ResultRelInfo * for tuple routing.

  9. Make RelationGetPartitionDispatchInfo expand depth-first.

  10. Expand partitioned tables in PartDesc order.

  11. Use a real RT index when setting up partition tuple routing.

  12. Fix transition tables for partition/inheritance.

  13. Fix confusion about number of subplans in partitioned INSERT setup.

  14. Prevent BEFORE triggers from violating partitioning constraints.

  15. Fire per-statement triggers on partitioned tables.

  16. Fix reporting of violations in ExecConstraints, again.

  17. Don't scan partitioned tables.

  18. Allow FDWs to push down quals without breaking EvalPlanQual rechecks.