Horton

Re: [HACKERS] Partition-wise aggregation/grouping

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Jeevan Chalke <jeevan.chalke@enterprisedb.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: 2018-03-22T16:58:03Z
Lists: pgsql-hackers 
On Thu, Mar 22, 2018 at 6:15 AM, Jeevan Chalke
<jeevan.chalke@enterprisedb.com> wrote:
> Leeks cleaner now. Thanks for refactoring it.
>
> I have merged these changes and flatten all previuos changes into the main
> patch.

Committed 0001-0005.  I made a few further modifications.  These were
mostly cosmetic, but with two exceptions:

1. I moved one set_cheapest() call to avoid doing that twice for the
top-level grouped_rel.

2. I removed the logic to set partition properties for grouped_rels.
As far as I can see, there's nothing that needs this.  It would be
important if we wanted subsequent planning stages to be able to do
partition-wise stuff, e.g. when doing window functions or setops, or
at higher query levels.  Maybe we'll have that someday; until then, I
think this is just a waste of cycles.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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.