Hello, The Wait processor has a property "Target Signal Count" which can be a number or expression language, and tells it how many signals to wait for.
-Bryan On Wed, May 10, 2017 at 9:58 PM, 尹文才 <[email protected]> wrote: > Hi Andrew, thanks for the link, I looked into the wait/notify mechanism > yesterday and found that one wait processor actually could only wait for > exactly one notify signal, but my case is like this: > Processor A, B and C， C has to wait for both flow files from A and B > conditionally, > if A and B all outputs flow files, C needs to wait for both flow files and > use both flow files to update data in C; > if either A or B doesn't emit flowfile, C also needs to use all incoming > flow files to update data > I could know in advance in up-stream processors whether A and B would > produce flowfiles, but I don't know if it's feasible with NIFI to implement > the following: > 1. use wait/notify to wait for multiple different signals(do I have to use > multiple wait processor chained in a flow to do it?) > 2. use wait/notify to conditionally wait for a signal > > Thanks, > > Ben > > 2017-05-10 11:49 GMT+08:00 Andrew Psaltis <[email protected]>: > >> Hi, >> I think the new Wait / Notify processors, can be used to solve this >> problem. Koji has a great blog post on it [1]. >> >> >> [1] http://ijokarumawak.github.io/nifi/2017/02/02/nifi-notify-batch/ >> >> Thanks, >> Andrew >> >> On Tue, May 9, 2017 at 11:43 PM, 尹文才 <[email protected]> wrote: >> >>> Hi guys, I'm currently using NiFi to do some ETL work and I need to >>> handle the following problem: >>> >>> for example I have 3 self-defined processor A, B and C. >>> all of them contain logic to incrementally update a database table. the >>> table in C is created by table in A join table in B, so C depends on the >>> flowfiles from A and B. >>> >>> So my question is is there a way for C to wait for both flowfiles from A >>> and B >>> to arrive and then start the work in C? Thanks. >>> >> >> >> >> -- >> Thanks, >> Andrew >> >> Subscribe to my book: Streaming Data <http://manning.com/psaltis> >> <https://www.linkedin.com/pub/andrew-psaltis/1/17b/306> >> twiiter: @itmdata <http://twitter.com/intent/user?screen_name=itmdata> >> > >
