Horton

Re: Parallel Aggregates for string_agg and array_agg

David Rowley <david.rowley@2ndquadrant.com>

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From: David Rowley <david.rowley@2ndquadrant.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Stephen Frost <sfrost@snowman.net>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-03-31T14:42:12Z
Lists: pgsql-hackers

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On 30 March 2018 at 02:55, Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote:
> On 03/29/2018 03:09 PM, David Rowley wrote:
>> I meant to mention earlier that I coded
>> agg_args_have_sendreceive_funcs() to only check for send/receive
>> functions. Really we could allow a byval types without send/receive
>> functions, since the serial/deserial just send the raw datums in that
>> case, but then the function becomes
>> agg_byref_args_have_sendreceive_funcs(), which seemed a bit obscure,
>> so I didn't do that.  Maybe I should?
>
> I'd do that. Not sure the function name needs to change, but perhaps
> agg_args_support_sendreceive() would be better - it covers both byref
> types (which require send/receive functions) and byval (which don't).

The attached patch implements this.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Fix unstable aggregate regression test

  2. Allow parallel aggregate on string_agg and array_agg

  3. Improve performance of ORDER BY / DISTINCT aggregates

  4. Support ORDER BY within aggregate function calls, at long last providing a

  5. Fix broken markup.