Horton

Re: [HACKERS] Partition-wise aggregation/grouping

Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>

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From: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>, Jeevan Chalke <jeevan.chalke@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2017-11-17T06:02:09Z
Lists: pgsql-hackers 
On Thu, Nov 16, 2017 at 6:02 AM, David Rowley
<david.rowley@2ndquadrant.com> wrote:
> On 16 November 2017 at 05:57, Konstantin Knizhnik
> <k.knizhnik@postgrespro.ru> wrote:
>> The main problem IMHO is that there are a lot of different threads and
>> patches related with this topic:(
>> And it is very difficult to combine all of them together to achieve the
>> final goal: efficient execution of OLAP queries on sharded table.
>> It will be nice if somebody who is making the most contribution in this
>> direction can somehow maintain it...
>> I just faced with particular problem with our pg_shardman extension and now
>> (thanks to your patch) I have some working solution for it.
>> But certainly I prefer to have this support in mainstream version of
>> Postgres.
>
> I don't think it's fair to be asking about additional features on this
> thread. It seems to me you're asking about two completely separate
> features, with the aim of trying to solve your own problems.
>
> It also looks to me that Jeevan has been clear on what his goals are
> for this patch. Perhaps what you're asking for is a logical direction
> to travel once this patch is committed, so I think, probably, the best
> way to conduct what you're after here is to either:
>
> a) Wait until this is committed and spin up your own thread about
> you're proposed changes to allow the PARTIAL aggregate to be pushed
> into the foreign server, or;
> b) Spin up your own thread now, with reference to this patch as a
> prerequisite to your own patch.
>
> I agree that what you're talking about is quite exciting stuff, but
> please, let's not talk about it here.
>

+1 for all that.


-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database 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.