Horton

Re: UPDATE of partition key

Amit Khandekar <amitdkhan.pg@gmail.com>

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From: Amit Khandekar <amitdkhan.pg@gmail.com>
To: Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Etsuro Fujita <fujita.etsuro@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: 2017-07-25T10:24:03Z
Lists: pgsql-hackers 
On 25 July 2017 at 15:02, Rajkumar Raghuwanshi
<rajkumar.raghuwanshi@enterprisedb.com> wrote:
> On Mon, Jul 24, 2017 at 11:23 AM, Amit Khandekar <amitdkhan.pg@gmail.com>
> wrote:
>>
>>
>> Attached update-partition-key_v13.patch now contains this
>> make_resultrels_ordered.patch changes.
>>
>
> I have applied attach patch and got below observation.
>
> Observation :  if join producing multiple output rows for a given row to be
> modified. I am seeing here it is updating a row and also inserting rows in
> target table. hence after update total count of table got incremented.

Thanks for catching this Rajkumar.

So after the row to be updated is already moved to another partition,
when the next join output row corresponds to the same row which is
moved, that row is now deleted, so ExecDelete()=>heap_delete() gets
HeapTupleSelfUpdated, and this is not handled. So even when
ExecDelete() finds that the row is already deleted, we still call
ExecInsert(), so a new row is inserted.  In ExecDelete(), we should
indicate that the row is already deleted. In the existing patch, there
is a parameter concurrenty_deleted for ExecDelete() which indicates
that the row is concurrently deleted. I think we can make this
parameter for both of these purposes so as to avoid ExecInsert() for
both these scenarios. Will work on a patch.

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.