Horton

Re: [HACKERS] Partition-wise aggregation/grouping

Jeevan Chalke <jeevan.chalke@enterprisedb.com>

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From: Jeevan Chalke <jeevan.chalke@enterprisedb.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: 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: 2018-03-08T14:32:22Z
Lists: pgsql-hackers 
On Thu, Mar 8, 2018 at 7:49 PM, Robert Haas <robertmhaas@gmail.com> wrote:

> On Thu, Mar 8, 2018 at 9:15 AM, Jeevan Chalke
> <jeevan.chalke@enterprisedb.com> wrote:
> > I am not sure why we don't set reltarget into the grouped_rel too.
> >
> > But if we do so like we did in partially_grouped_rel, then it will be lot
> > easier for partitionwise aggregate as then we don't have to pass target
> to
> > functions creating paths like create_append_path. We now need to update
> > generate_gather_paths() to take target too as it is now being called on
> > grouped_rel in which reltarget is not set.
> >
> > But yes, if there is any specific reason we can't do so, then I think the
> > same like Ashutosh Said. I didn't aware of such reason though.
>
> I see no problem with setting reltarget for the grouped_rel.  Before
> we added partially_grouped_rel, that rel computed paths with two
> different targets: partial paths had the partial grouping target, and
> non-partial paths had the ordinary grouping target.  But that's fixed
> now.
>

OK.
Will update my changes accordingly.
If we set reltarget into the grouped_rel now, then I don't need one of the
refactoring patch which is passing target to the path creation functions.


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



-- 
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.