Thank you Jiayi, that helps a lot! On Fri, 29 Nov 2019 at 13:44, bupt_ljy <bupt_...@163.com> wrote:
> Hi Shuwen, > > > > When to call close() ? After every element processed? Or > on ProcessFunction.close() ? Or never to use it? > > > IMO, the #close() function is used to manage the lifecycle of #Collector > instead of a single element. I think it should not be called in user > function unless you have some special use cases(no use case comes to my > mind). > > > > If it's been closed already, can the collector collect() anymore data? > > > No. if it’s closed, it usually means the writer is closed or maybe the > operator is closed. > > > > If processElement received a message but consider it as discard and > does not call collect(), will this block checkpoint's barrier until next > element was sent by collect() ? > > > No. > > > > Best, > > Jiayi Liao > > > > Original Message > *Sender:* shuwen zhou<jaco...@gmail.com> > *Recipient:* user<user@flink.apache.org> > *Date:* Friday, Nov 29, 2019 12:29 > *Subject:* ProcessFunction collect and close, when to use? > > Hi Community, > In ProcessFunction class, ProcessElement function, there is a Collector > that has 2 method: collect() and close(). I would like to know: > > 1. When to call close() ? After every element processed? Or > on ProcessFunction.close() ? Or never to use it? If it's been closed > already, can the collector collect() anymore data? > 2. If processElement received a message but consider it as discard and > does not call collect(), will this block checkpoint's barrier until next > element was sent by collect() ? > > > -- > Best Wishes, > Shuwen Zhou > > -- Best Wishes, Shuwen Zhou
