Horton

Re: [HACKERS] UPDATE of partition key

David Rowley <david.rowley@2ndquadrant.com>

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From: David Rowley <david.rowley@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Amit Khandekar <amitdkhan.pg@gmail.com>, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, pgsql-hackers <pgsql-hackers@postgresql.org>, Thomas Munro <thomas.munro@enterprisedb.com>
Date: 2018-01-16T03:47:28Z
Lists: pgsql-hackers 
On 16 January 2018 at 01:09, Robert Haas <robertmhaas@gmail.com> wrote:
> On Sun, Jan 14, 2018 at 6:57 AM, Amit Khandekar <amitdkhan.pg@gmail.com> wrote:
>> Even where partitions are present, in the usual case where there are
>> Instead of a bool array, we can even make it a Bitmapset. But I think
>> access would become slower as compared to array, particularly because
>> it is going to be a heavily used function.
>
> It probably makes little difference -- the Bitmapset will be more
> compact (which saves time) but involve function calls (which cost
> time).

I'm not arguing in either direction, but you'd also want to factor in
how Bitmapsets only allocate words for the maximum stored member,
which might mean multiple realloc() calls resulting in palloc/memcpy
calls. The array would just be allocated in a single chunk, although
it would be more memory and would require a memset too, however,
that's likely much cheaper than the palloc() anyway.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

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.