Song: You can put an operator as the very first node in the DAG, and have everything else in the DAG depend on it. For example, this is the approach we use to only execute DAG tasks on stock market trading days.
-James M. On Fri, May 11, 2018 at 3:57 AM, Song Liu <song...@outlook.com> wrote: > Hi, > > I have something just want to be done only once when DAG is constructed, > but it seems that DAG will be instanced every time when run each of > operator. > > So is that there function in DAG that tell us it is starting to run now ? > > Thanks, > Song >
