Horton

Re: UPDATE of partition key

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: Amit Khandekar <amitdkhan.pg@gmail.com>, Greg Stark <stark@mit.edu>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-02-24T08:30:39Z
Lists: pgsql-hackers 
On Fri, Feb 24, 2017 at 1:18 PM, David G. Johnston
<david.g.johnston@gmail.com> wrote:
> For my own sanity - the move update would complete successfully and break
> every ctid chain that it touches.  Any update lined up behind it in the lock
> queue would discover their target record has been deleted and would
> experience whatever behavior their isolation level dictates for such a
> situation.  So multi-partition update queries will fail to update some
> records if they happen to move between partitions even if they would
> otherwise match the query's predicate.

Right.  That's the behavior for which I am advocating, on the grounds
that it's the simplest to implement and if we all agree on something
else more complicated later, we can do it then.

> Is there any difference in behavior between this and a SQL writeable CTE
> performing the same thing via delete-returning-insert?

Not to my knowledge.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL 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.