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Re: [Sender Address Forgery]Re: Postgres 11 release notes

Amit Langote <langote_amit_f8@lab.ntt.co.jp>

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From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: Bruce Momjian <bruce@momjian.us>, Amit Langote <amitlangote09@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-05-23T01:28:41Z
Lists: pgsql-hackers 
On 2018/05/23 10:16, Bruce Momjian wrote:
> On Sat, May 19, 2018 at 12:58:04AM +0900, Amit Langote wrote:
>> Hi Bruce.
>>
>> On Tue, May 15, 2018 at 12:46 PM, Amit Langote
>> <Langote_Amit_f8@lab.ntt.co.jp> wrote:
>>> On 2018/05/15 5:30, Bruce Momjian wrote:
>>>> I like it, done.
>>>
>>> Thank you.
>>
>> I wonder what you think about including this little performance item:
>>
>> https://www.postgresql.org/message-id/E1eotSQ-0005V0-LV@gemulon.postgresql.org
>>
>> especially considering the part of the commit message which states
>>
>> ...Still, testing shows
>> that this makes single-row inserts significantly faster on a table
>> with many partitions without harming the bulk-insert case.
>>
>> I recall seeing those inserts being as much as 2x faster as partition
>> count grows beyond hundreds.  One might argue that we should think
>> about publicizing this only after we've dealt with the
>> lock-all-partitions issue that's also mentioned in the commit message
>> which is still a significant portion of the time spent and I'm totally
>> fine with that.
> 
> Uh, we already have this in the release notes:
> 
>         Allow faster partition elimination during query processing (Amit
>         Langote, David Rowley, Dilip Kumar)
> 
>         This speeds access to partitioned tables with many partitions.
> 
> Do you want me to add the git commit hash to this release note entry?

I suppose you meant the above as an entry for performance improvement of
partition "pruning".  The commit I quoted is concerned with making "tuple
routing" a bit faster, but as David said that's not making it as fast as
it could really be.  So, we should hold off from touting it as an
improvement at this point and I have to agree.  Sorry for the noise.

Thanks,
Amit

Commits

  1. doc: update PG 11 release notes

  2. Fix misspelled pg_trgm contrib name in PostgreSQL 11 release notes

  3. Doc: clarify release note text about v11's new window function features.

  4. Improve wording of release notes item

  5. Fix typos in release notes

  6. Doc: preliminary list of PG11 major features.

  7. Make numeric power() handle NaNs according to the modern POSIX spec.

  8. Various improvements of skipping index scan during vacuum technics

  9. Revert back-branch changes in power()'s behavior for NaN inputs.

  10. Avoid wrong results for power() with NaN input on more platforms.

  11. Avoid wrong results for power() with NaN input on some platforms.

  12. Skip full index scan during cleanup of B-tree indexes when possible

  13. Rewrite the code that applies scan/join targets to paths.

  14. Postpone generate_gather_paths for topmost scan/join rel.

  15. Add casts from jsonb

  16. Make plpgsql use its DTYPE_REC code paths for composite-type variables.

  17. Don't allow VACUUM VERBOSE ANALYZE VERBOSE.

  18. Pass InitPlan values to workers via Gather (Merge).

  19. Account for the effect of lossy pages when costing bitmap scans.

  20. Allow no-op GiST support functions to be omitted.

  21. Rearm statement_timeout after each executed query.

  22. Push limit through subqueries to underlying sort, where possible.