I guess trait really feels different from your config. I guess `Context`
is where you are looking for, see below.
/**
* Does nothing.
*
* @deprecated Previously, this method installed the cancellation-checking
* flag for this planner, but is now deprecated. Now, you should add a
* {@link CancelFlag} to the {@link Context} passed to the constructor.
*
* @param cancelFlag flag which the planner should periodically check
*/
@Deprecated // to be removed before 2.0
void setCancelFlag(CancelFlag cancelFlag);
On Fri, Jan 18, 2019 at 9:35 AM Hequn Cheng <[email protected]> wrote:
> Hi Stamatis,
>
> Thanks a lot for your reply. Yes, it seems the traits currently in Calcite
> are used by the optimizer. I wonder whether we can extend it for other
> use-cases. For example, I want to provide a way to the users that they can
> set memory or cpu settings for an aggregate node from the user api. These
> settings will only be used after optimization.
>
> I haven't found other ways to achieve this, so maybe using trait is a neat
> way?
>
> Best, Hequn
>
>
> On Fri, Jan 18, 2019 at 12:00 AM Stamatis Zampetakis <[email protected]>
> wrote:
>
> > Hi Hequn,
> >
> > I would describe traits as properties associated with RelNodes that
> provide
> > useful information to the optimizer (rules etc.) in order to generate a
> > plan.
> >
> > If the configuration you are referring to is meant to guide the optimizer
> > in generating a plan then it seems ok to use traits. If not then probably
> > you need something different.
> >
> > Can you elaborate a bit more on your usecase?
> >
> > Best,
> > Stamatis
> >
> >
> > On Tue, Jan 15, 2019, 10:57 AM Hequn Cheng <[email protected] wrote:
> >
> > > Hi Julian,
> > >
> > > Thanks a lot for your reply and the detailed explanation. It solves my
> > > doubts well.
> > > My custom trait only contains one value, so I think that there will not
> > be
> > > a problem.
> > >
> > > May I further the email with another question:
> > > Is it ok or right to use a trait to pass configurations through
> RelNodes?
> > > For example, a configuration set from api for the aggregate and used
> > after
> > > the optimization.
> > > If not, are there any standard ways to achieve this?
> > >
> > > I haven't found any clear definition about trait. Only find comments in
> > > code: *RelTrait represents the manifestation of a relational expression
> > > trait within a trait definition.*
> > >
> > > Thank you!
> > >
> > > On Tue, Jan 15, 2019 at 3:12 AM Julian Hyde <[email protected]> wrote:
> > >
> > > > In most cases increasing the number of traits from one to two will
> > > > increase the planning time by a negligible amount.
> > > >
> > > > But it can increase the size of the search space. Suppose a
> particular
> > > > relational expression has 5 possible sort orders (order by x, order
> by
> > x,
> > > > y, order by (), order by z, order by x, z), and initially you have
> only
> > > the
> > > > collation trait enabled. A particular equivalence set might have 5
> > > subsets,
> > > > one for each sort order. Now let’s suppose you add the distribution
> > trait
> > > > to the mix, and there are 3 distributions (partition by (), partition
> > by
> > > x,
> > > > partition by z). Now that subset will have 15 subsets, for the
> > cartesian
> > > > product of the traits.
> > > >
> > > > A larger search space could increase the planning time (and memory
> > usage)
> > > > significantly.
> > > >
> > > > But if each trait has only one or two values I doubt that there will
> > be a
> > > > problem.
> > > >
> > > > Julian
> > > >
> > > >
> > > > > On Jan 14, 2019, at 1:38 AM, Hequn Cheng <[email protected]>
> > wrote:
> > > > >
> > > > > Hi everyone,
> > > > >
> > > > > I want to pass properties through RelNodes via trait and I wonder
> if
> > > the
> > > > > number of traits in traitSet will affect the time of Volcano
> > > > optimization.
> > > > > For example, increasing one traitDef to two in VolcanoPlanner.
> > > > >
> > > > > I guess the answer is No. Is it correct?
> > > > > As long as the search space is not increased, the Volcano
> > optimization
> > > > time
> > > > > will not increase. And simply increasing the number of traits alone
> > > does
> > > > > not add complexity.
> > > > >
> > > > > Furthermore, besides time, are there any other side effects if I
> > > increase
> > > > > the number of traits?
> > > > >
> > > > > Thank you very much!
> > > > >
> > > > > Best,
> > > > > Hequn
> > > >
> > > >
> > >
> >
>
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no mistakes
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