Re: Rename max_parallel_degree?

On Mon, Apr 25, 2016 at 12:17:56PM +0200, Magnus Hagander wrote:
>
>
> On Mon, Apr 25, 2016 at 5:01 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Sun, Apr 24, 2016 at 2:42 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Magnus Hagander <magnus(at)hagander(dot)net> writes:
> >> On Sun, Apr 24, 2016 at 8:23 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >>> FWIW, I agree with Bruce that using "degree" here is a poor choice.
> >>> It's an unnecessary dependence on technical terminology that many
> people
> >>> will not be familiar with.
> >
> >> FWIW, SQL Server calls it "degree of parallelism" as well (
> >> https://technet.microsoft.com/en-us/library/ms188611(v=sql.105).aspx).
> And
> >> their configuration option is "max degree of parallelism":
> >> https://technet.microsoft.com/en-us/library/ms181007(v=sql.105).aspx.
> >
> > Yes, but both they and Oracle appear to consider "degree" to mean the
> > total number of processors used, not the number of secondary jobs in
> > addition to the main one.  The only thing worse than employing obscure
> > technical terminology is employing it incorrectly: that way, you get to
> > confuse both the users who know what it means and those who don't.
>
> This is not so clear-cut as you are making it out to be.  For example,
> see http://www.akadia.com/services/ora_parallel_processing.html - viz
> "The number of parallel slave processes associated with an operation
> is called its degree of parallelism", which is pretty close to what
> the parameter currently called max_parallel_degree actually does.
>
>
>
> So maybe something like  session_parallel_degree, to add another color to the
> bikeshed?

I think Robert said it is per-executor node, not per session, similar to
work_mem.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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