Re: [HACKERS] Small improvement to parallel query docs
От | Amit Kapila |
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Тема | Re: [HACKERS] Small improvement to parallel query docs |
Дата | |
Msg-id | CAA4eK1K3MY5CQcHRYCYNFiXFqo3C82N1Mm_Pz2D67Fo6H7ZgGg@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: [HACKERS] Small improvement to parallel query docs (David Rowley <david.rowley@2ndquadrant.com>) |
Ответы |
Re: [HACKERS] Small improvement to parallel query docs
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Список | pgsql-hackers |
On Tue, Feb 14, 2017 at 3:33 AM, David Rowley <david.rowley@2ndquadrant.com> wrote: > On 14 February 2017 at 10:56, Brad DeJong <Brad.Dejong@infor.com> wrote: >> David Rowley wrote: >>> I propose we just remove the whole paragraph, and mention about >>> the planning and estimated number of groups stuff in another new paragraph. >>> >>> I've attached a patch to this effect ... >> >> s/In a worse case scenario/In the worst case scenario,/ >> >> Other than that, the phrasing in the new patch reads very smoothly. > > Thanks. Updated patch attached. > > + Aggregate</> stage. For such cases there is clearly going to be no + performance benefit to using parallel aggregation. A comma is required after "For such cases" > The query planner takes > + this into account during the planning process and will choose how to > + perform the aggregation accordingly. This part of the sentence sounds unclear. It doesn't clearly indicate that planner won't choose a parallel plan in such cases. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
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