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: Robert Haas <robertmhaas@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-06-19T22:12:15Z
Lists: pgsql-hackers 
On Fri, Jun 16, 2017 at 5:36 AM, Amit Khandekar <amitdkhan.pg@gmail.com> wrote:
> There is another issue I discovered. The row-movement works fine if
> the destination leaf partition has different attribute ordering than
> the root : the existing insert-tuple-routing mapping handles that. But
> if the source partition has different ordering w.r.t. the root, it has
> a problem : there is no mapping in the opposite direction, i.e. from
> the leaf to root. And we require that because the tuple of source leaf
> partition needs to be converted to root partition tuple descriptor,
> since ExecFindPartition() starts with root.
>
> To fix this, I have introduced another mapping array
> mtstate->mt_resultrel_maps[]. This corresponds to the
> mtstate->resultRelInfo[]. We don't require per-leaf-partition mapping,
> because the update result relations are pruned subset of the total
> leaf partitions.

Hi Amit & Amit,

Just a thought: If I understand correctly this new array of tuple
conversion maps is the same as mtstate->mt_transition_tupconv_maps in
my patch transition-tuples-from-child-tables-v11.patch (hopefully soon
to be committed to close a PG10 open item).  In my patch I bounce
transition tuples from child relations up to the named relation's
triggers, and in this patch you bounce child tuples up to the named
relation for rerouting, so the conversion requirement is the same.
Perhaps we could consider refactoring to build a common struct member
on demand for the row movement patch at some point in the future if it
makes the code cleaner.

-- 
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.