Horton

Re: Partition-wise aggregation/grouping

Jeevan Chalke <jeevan.chalke@enterprisedb.com>

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From: Jeevan Chalke <jeevan.chalke@enterprisedb.com>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: David Rowley <david.rowley@2ndquadrant.com>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2017-10-17T17:14:22Z
Lists: pgsql-hackers 
On Tue, Oct 17, 2017 at 7:13 PM, Dilip Kumar <dilipbalaut@gmail.com> wrote:

> On Fri, Oct 13, 2017 at 12:06 PM, Jeevan Chalke
> <jeevan.chalke@enterprisedb.com> wrote:
> >
> While playing around with the patch I have noticed one regression with
> the partial partition-wise aggregate.
>
> I am consistently able to reproduce this on my local machine.
>
> Scenario: Group by on non-key column and only one tuple per group.
>

I didn't get what you mean by regression here. Can you please explain?

I see that PWA plan is selected over regular plan when enabled on the basis
of costing.
Regular planning need a Result node due to which costing increases where as
PWA don't need that and thus wins.


-- 
Jeevan Chalke
Technical Architect, Product Development
EnterpriseDB Corporation
The Enterprise PostgreSQL Company

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.