Hi Yingyi, I see. Thanks for your reply:-)
Bests, Mingda On Mon, Oct 31, 2016 at 11:23 AM, Yingyi Bu <[email protected]> wrote: > Mingda, > > I'm not sure how much re-ordering can be done at the Hyracks level, > i.e., the runtime level. > In the optimizer (the asterixdb/algebricks level), we don't have > re-ordering for joins, because: > --- the cost model has not been added yet. I'm not sure about the > timeline for this. @Ildar? > --- respecting user-specified join orders is important for certain > cases, for example, to get stable/predictable performance (zero surprise) > for applications. > > In the runtime, we have a role-reversal optimization in hybrid hash > join, which is a safe optimization that is not based on estimations. You > can look at OptimizedHybridHashJoin. > > Best, > Yingyi > > > On Mon, Oct 31, 2016 at 11:16 AM, mingda li <[email protected]> > wrote: > > > Dear all, > > > > Hi, I am working on multiple join on Hyracks level. I am not sure if I do > > the multiple join on AsterixDB, whether it will optimize the query by > > changing the join order or just execute according to how we write the > > query. I think this may not be done in Algebricks level based on rule but > > not sure. > > > > Bests, > > Mingda > > >
