Horton

Re: [HACKERS] Partition-wise aggregation/grouping

David Steele <david@pgmasters.net>

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From: David Steele <david@pgmasters.net>
To: Jeevan Chalke <jeevan.chalke@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Dilip Kumar <dilipbalaut@gmail.com>, David Rowley <david.rowley@2ndquadrant.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2018-04-10T14:00:24Z
Lists: pgsql-hackers 
Hi Jeevan,

On 4/2/18 10:57 AM, Robert Haas wrote:
> On Thu, Mar 29, 2018 at 9:02 AM, Jeevan Chalke
> <jeevan.chalke@enterprisedb.com> wrote:
>> Yep, I see the risk.
> 
> Committed 0001 last week and 0002 just now.  I don't really see 0003 a
> a critical need.  If somebody demonstrates that this saves a
> meaningful amount of planning time, we can consider that part for a
> future release.

The bulk of this patch was committed so I have marked it that way.

If you would like to pursue patch 03 I think it would be best to start a
new thread and demonstrate how the patch will improve performance.

Regards,
-- 
-David
david@pgmasters.net

Commits

  1. postgres_fdw: Push down partition-wise aggregation.

  2. Remove 'target' from GroupPathExtraData.

  3. Implement partition-wise grouping/aggregation.

  4. Don't pass the grouping target around unnecessarily.

  5. Determine grouping strategies in create_grouping_paths.

  6. Defer creation of partially-grouped relation until it's needed.

  7. Split create_grouping_paths into degenerate and non-degenerate cases.

  8. Pass additional arguments to a couple of grouping-related functions.

  9. Fix logic error in add_paths_to_partial_grouping_rel.

  10. Minor cleanup of code related to partially_grouped_rel.

  11. Add a new upper planner relation for partially-aggregated results.

  12. Charge cpu_tuple_cost * 0.5 for Append and MergeAppend nodes.

  13. Rename enable_partition_wise_join to enable_partitionwise_join

  14. Factor some code out of create_grouping_paths.

  15. Pad XLogReaderState's main_data buffer more aggressively.

  16. Prevent int128 from requiring more than MAXALIGN alignment.

  17. Fix DROP SUBSCRIPTION hang

  18. Inject $(ICU_LIBS) regardless of platform.

  19. Some preliminary refactoring towards partitionwise join.