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Re: [HACKERS] UPDATE of partition key

Amit Khandekar <amitdkhan.pg@gmail.com>

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From: Amit Khandekar <amitdkhan.pg@gmail.com>
To: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Thomas Munro <thomas.munro@enterprisedb.com>
Date: 2017-11-30T13:18:13Z
Lists: pgsql-hackers

Attachments

On 29 November 2017 at 17:25, Amit Khandekar <amitdkhan.pg@gmail.com> wrote:
> Also, this
> patch contains the incremental changes that were attached in the patch
> encapsulate_partinfo.patch attached in [1]. In the next version, I
> will extract them out again and keep them as a separate preparatory
> patch.

As mentioned above, attached is
encapsulate_partinfo_preparatory.patch. This addresses David Rowley's
request to move all the partition-related information into new
structure PartitionTupleRouting, so that for
ExecSetupPartitionTupleRouting(), we could pass pointer to this
structure  instead of the many parameters that we currently pass: [1]

The main update-partition-key patch is to be applied over the above
preparatory patch. Attached is its v27 version. This version addresses
Thomas Munro's comments :

On 14 November 2017 at 01:32, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> On Fri, Nov 10, 2017 at 4:42 PM, Amit Khandekar <amitdkhan.pg@gmail.com> wrote:
>> Attached is v23 patch that has just the above changes (and also
>> rebased on hash-partitioning changes, like update.sql). I am still
>> doing some sanity testing on this, although regression passes.
>
> The test coverage[1] is 96.62%.  Nice work.  Here are the bits that
> aren't covered:
>
> In partition.c's pull_child_partition_columns(), the following loop is
> never run:
>
> +       foreach(lc, partexprs)
> +       {
> +               Node       *expr = (Node *) lfirst(lc);
> +
> +               pull_varattnos(expr, 1, &child_keycols);
> +       }

In update.sql, part_c_100_200 is now partitioned by range(abs(d)). So
now the new function has_partition_atttrs() (in recent patch versions,
this function has replaced pull_child_partition_columns) goes through
the above code segment. This was indeed an important part left
uncovered. Thanks.

>
> In nodeModifyTable.c, the following conditional branches are never run:
>
>                 if (mtstate->mt_oc_transition_capture != NULL)
> +               {
> +                       Assert(mtstate->mt_is_tupconv_perpart == true);
>                         mtstate->mt_oc_transition_capture->tcs_map =
> -
> mtstate->mt_transition_tupconv_maps[leaf_part_index];
> +
> mtstate->mt_childparent_tupconv_maps[leaf_part_index];
> +               }

I think this code segment never hits even without the patch. For
partitions, ON CONFLICT is not supported, and this code segment runs
only for partitions.

>
>
>                                 if (node->mt_oc_transition_capture != NULL)
>                                 {
> -
> Assert(node->mt_transition_tupconv_maps != NULL);
>
> node->mt_oc_transition_capture->tcs_map =
> -
> node->mt_transition_tupconv_maps[node->mt_whichplan];
> +
> tupconv_map_for_subplan(node, node->mt_whichplan);
>                                 }

Here also, I verified that none of the regression tests hits this
segment. The reason might be : this segment is run when an UPDATE
starts with the next subplan, and mtstate->mt_oc_transition_capture is
never allocated for UPDATEs.


[1] : https://www.postgresql.org/message-id/CAJ3gD9f86H64e4OCjFFszWW7f4EeyriSaFL8SvJs2yOUbc8VEw%40mail.gmail.com

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

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.