Hi there, I just updated the doc <https://docs.google.com/document/d/1372B7HYxtcUYjZOnOM7OBTfSJ4CyFg_gaPD_NUxWClo/edit?usp=sharing> with implementation details and opened PR13105 <https://github.com/apache/beam/pull/13105> for review.
Thanks for your help! On Wed, Oct 14, 2020 at 3:40 AM Maximilian Michels <m...@apache.org> wrote: > Duplicates cannot happen because the state of all operators will be > rolled back to the latest checkpoint, in case of failures. > > On 14.10.20 06:31, Reuven Lax wrote: > > Does this mean that we have to deal with duplicate messages over the > > back edge? Or will that not happen, since duplicates mean that we rolled > > back a checkpoint. > > > > On Tue, Oct 13, 2020 at 2:59 AM Maximilian Michels <m...@apache.org > > <mailto:m...@apache.org>> wrote: > > > > There would be ways around the lack of checkpointing in cycles, e.g. > > buffer and backloop only after checkpointing is complete, similarly > how > > we implement @RequiresStableInput in the Flink Runner. > > > > -Max > > > > On 07.10.20 04:05, Reuven Lax wrote: > > > It appears that there's a proposal > > > > > ( > https://cwiki.apache.org/confluence/display/FLINK/FLIP-16%3A+Loop+Fault+Tolerance > > < > https://cwiki.apache.org/confluence/display/FLINK/FLIP-16%3A+Loop+Fault+Tolerance > > > > > > > > > < > https://cwiki.apache.org/confluence/display/FLINK/FLIP-16%3A+Loop+Fault+Tolerance > > < > https://cwiki.apache.org/confluence/display/FLINK/FLIP-16%3A+Loop+Fault+Tolerance > >>) > > > > > and an abandoned PR to fix this, but AFAICT this remains a > > limitation of > > > Flink. If Flink can't guarantee processing of records on back > > edges, I > > > don't think we can use cycles, as we might otherwise lose the > > residuals. > > > > > > On Tue, Oct 6, 2020 at 6:16 PM Reuven Lax <re...@google.com > > <mailto:re...@google.com> > > > <mailto:re...@google.com <mailto:re...@google.com>>> wrote: > > > > > > This is what I was thinking of > > > > > > "Flink currently only provides processing guarantees for jobs > > > without iterations. Enabling checkpointing on an iterative job > > > causes an exception. In order to force checkpointing on an > > iterative > > > program the user needs to set a special flag when enabling > > > checkpointing:|env.enableCheckpointing(interval, > > > CheckpointingMode.EXACTLY_ONCE, force = true)|. > > > > > > Please note that records in flight in the loop edges (and the > > state > > > changes associated with them) will be lost during failure." > > > > > > > > > > > > > > > > > > > > > On Tue, Oct 6, 2020 at 5:44 PM Boyuan Zhang > > <boyu...@google.com <mailto:boyu...@google.com> > > > <mailto:boyu...@google.com <mailto:boyu...@google.com>>> > wrote: > > > > > > Hi Reuven, > > > > > > As Luke mentioned, at least there are some limitations > around > > > tracking watermark with flink cycles. I'm going to use > > State + > > > Timer without flink cycle to support self-checkpoint. For > > > dynamic split, we can either explore flink cycle approach > or > > > limit depth approach. > > > > > > On Tue, Oct 6, 2020 at 5:33 PM Reuven Lax > > <re...@google.com <mailto:re...@google.com> > > > <mailto:re...@google.com <mailto:re...@google.com>>> > wrote: > > > > > > Aren't there some limitations associated with flink > > cycles? > > > I seem to remember various features that could not be > > used. > > > I'm assuming that watermarks are not supported across > > > cycles, but is there anything else? > > > > > > On Tue, Oct 6, 2020 at 7:12 AM Maximilian Michels > > > <m...@apache.org <mailto:m...@apache.org> > > <mailto:m...@apache.org <mailto:m...@apache.org>>> wrote: > > > > > > Thanks for starting the conversation. The two > > approaches > > > both look good > > > to me. Probably we want to start with approach #1 > for > > > all Runners to be > > > able to support delaying bundles. Flink supports > > cycles > > > and thus > > > approach #2 would also be applicable and could be > > used > > > to implement > > > dynamic splitting. > > > > > > -Max > > > > > > On 05.10.20 23:13, Luke Cwik wrote: > > > > Thanks Boyuan, I left a few comments. > > > > > > > > On Mon, Oct 5, 2020 at 11:12 AM Boyuan Zhang > > > <boyu...@google.com <mailto:boyu...@google.com> > > <mailto:boyu...@google.com <mailto:boyu...@google.com>> > > > > <mailto:boyu...@google.com > > <mailto:boyu...@google.com> > > > <mailto:boyu...@google.com > > <mailto:boyu...@google.com>>>> wrote: > > > > > > > > Hi team, > > > > > > > > I'm looking at adding self-checkpoint > > support to > > > portable Flink > > > > runner(BEAM-10940 > > > > > > <https://issues.apache.org/jira/browse/BEAM-10940 > > <https://issues.apache.org/jira/browse/BEAM-10940> > > > <https://issues.apache.org/jira/browse/BEAM-10940 > > <https://issues.apache.org/jira/browse/BEAM-10940>>>) for > > > both batch > > > > and streaming. I summarized the problem > > that we > > > want to solve and > > > > proposed 2 potential approaches in this doc > > > > > > > > > < > https://docs.google.com/document/d/1372B7HYxtcUYjZOnOM7OBTfSJ4CyFg_gaPD_NUxWClo/edit?usp=sharing > < > https://docs.google.com/document/d/1372B7HYxtcUYjZOnOM7OBTfSJ4CyFg_gaPD_NUxWClo/edit?usp=sharing> > < > https://docs.google.com/document/d/1372B7HYxtcUYjZOnOM7OBTfSJ4CyFg_gaPD_NUxWClo/edit?usp=sharing > < > https://docs.google.com/document/d/1372B7HYxtcUYjZOnOM7OBTfSJ4CyFg_gaPD_NUxWClo/edit?usp=sharing > >>>. > > > > > > > > I want to collect feedback on which > > approach is > > > preferred and > > > > anything that I have not taken into > > consideration > > > yet but I should. > > > > Many thanks to all your help! > > > > > > > > Boyuan > > > > > > > > > >
