Horton

Re: [HACKERS] Partition-wise aggregation/grouping

Andres Freund <andres@anarazel.de>

View thread View on postgr.es
From: Andres Freund <andres@anarazel.de>
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: 2018-03-26T22:03:23Z
Lists: pgsql-hackers 
Hi,

On 2018-03-23 17:01:54 +0530, Jeevan Chalke wrote:
> Attached patch which fixes that.

Thanks, will push. For the future, I'd be more likely to notice if you
CC me ;)


> However, I am not sure whether it is expected to have stable regression run
> with installcheck having local settings.
> For example, If I have enabale_hashagg = false locally; I will definitely
> see failures.
> 
> ISTM, that I am missing Andres point here.

I don't think there's a hard and fast rule here. I personally often
during development disable parallelism because it makes some things
harder (you can't easily debug crashes with gdb, benchmarks show larger
variance, ...).  There doesn't seem to be an equivalent benefit to
support running e.g. with enabale_hashagg = false.

- Andres

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.