| From: | Julien Rouhaud <julien(dot)rouhaud(at)dalibo(dot)com> |
|---|---|
| To: | James Sewell <james(dot)sewell(at)lisasoft(dot)com>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Paul Ramsey <pramsey(at)cleverelephant(dot)ca> |
| Subject: | Re: Choosing parallel_degree |
| Date: | 2016-03-22 06:58:05 |
| Message-ID: | 56F0ECFD.9070304@dalibo.com |
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| Thread: | |
| Lists: | pgsql-hackers |
On 21/03/2016 20:38, Julien Rouhaud wrote:
> On 21/03/2016 05:18, James Sewell wrote:
>> OK cool, thanks.
>>
>> Can we remove the minimum size limit when the per table degree setting
>> is applied?
>>
>> This would help for tables with 2 - 1000 pages combined with a high CPU
>> cost aggregate.
>>
>
> Attached v4 implements that. It also makes sure that the chosen
> parallel_degree won't be more than the relation's estimated number of pages.
>
And I just realize that it'd prevent from forcing parallelism on
partitionned table, v5 attached removes the check on the estimated
number of pages.
--
Julien Rouhaud
http://dalibo.com - http://dalibo.org
| Attachment | Content-Type | Size |
|---|---|---|
| rel_parallel_degree_v5.diff | text/plain | 6.7 KB |
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