> On Aug. 26, 2016, 7:51 p.m., Chris Pettitt wrote: > > samza-api/src/main/java/org/apache/samza/system/IncomingMessageEnvelope.java, > > line 31 > > <https://reviews.apache.org/r/51346/diff/4/?file=1486375#file1486375line31> > > > > How likely are we to collide with this? Thats the problem with using a > > user definable token. I see two options: > > > > If null is not supported (and thus not usable by user-defined > > implementations) I would use that and mark it as reserved. > > > > Otherwise I would probably do something more to make this unlikely to > > collide (call me paranoid). Something like use a NUL byte as the first > > character and document that offsets with such an encoding are reserved. I > > would also check that this sort of string doesn't make it to user code in > > the task. > > Jagadish Venkatraman wrote: > Returning a null is not possible (because a null offset could mean that > we don't have messages at this moment instead of meaning end-of-stream. While > we should poll again when a consumer returns null, we should not for the > END_OF_STREAM case.) Hence, I was hoping to use a special offset. > > I like your suggestion of using a NUL byte as the first character (and > calling that out). I'll update the RB with that. > > Jagadish Venkatraman wrote: > There seem to be inter-operability versions of strings in Java vs strings > in scala (esp - around handling NUL bytes in the string- Scala appears to > strip out NUL bytes). Hence, I've used a "SAMZA_INTERNAL_END_OF_STREAM" as a > string. Let me know if there's a better way to handle this.
Scala should definitely not be dropping any bytes. How could it safely do so? FWIW, you can verify: ``` % scala scala> "\u0000".length res0: Int = 1 ``` - Chris ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/51346/#review147015 ----------------------------------------------------------- On Aug. 30, 2016, 12:32 a.m., Jagadish Venkatraman wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/51346/ > ----------------------------------------------------------- > > (Updated Aug. 30, 2016, 12:32 a.m.) > > > Review request for samza, Boris Shkolnik, Chris Pettitt, Yi Pan (Data > Infrastructure), Navina Ramesh, and Xinyu Liu. > > > Repository: samza > > > Description > ------- > > Samza currently works with unbounded data sources (kafka streams). However, > for bounded data sources like HDFS files, snapshot files which are not > infinite, we need a notion of 'end-of-stream'. > > This is a step towards realizing a 'finite' Samza job that terminates once > data processing is complete.(as opposed to an infinite stream job that keeps > running) > > RB changes: > - New interface for EndOfStreamListener > - New 'end-of-stream' state in the state-machine of AsyncStreamTask > (Invariant: When end-of-stream is reached there are no buffered messages, > no-callbacks are in-flight and no-window or commit call shall be in progress) > - Changes to allow clean shut-downs of the tasks/container/job for > end-of-stream. > > Design Doc and Implementation Notes: > https://issues.apache.org/jira/secure/attachment/12825119/ProposalforEndofStreaminSamza.pdf > > > Diffs > ----- > > build.gradle 1d4eb74b1294318db8454631ddd0901596121ab2 > > samza-api/src/main/java/org/apache/samza/system/IncomingMessageEnvelope.java > cc860cf7eb4d514736913c1dceaa80534b61d71a > > samza-api/src/main/java/org/apache/samza/system/SystemStreamPartitionIterator.java > a8f858aa7e4f4ce436f450cf439fe1a102983c64 > samza-api/src/main/java/org/apache/samza/task/EndOfStreamListenerTask.java > PRE-CREATION > samza-core/src/main/java/org/apache/samza/task/AsyncRunLoop.java > a510bb0c5914c772438930d27f100b4d360c1296 > samza-core/src/main/java/org/apache/samza/task/AsyncStreamTaskAdapter.java > 1fc645673b7547b642830df5639c0b4fcd11c0d5 > samza-core/src/main/scala/org/apache/samza/container/TaskInstance.scala > 89f6857014489aba2db4129bc2e26dfec5b10652 > samza-core/src/test/java/org/apache/samza/task/TestAsyncRunLoop.java > ca913dea79fecbcecdfd1010dc794318055c5764 > > Diff: https://reviews.apache.org/r/51346/diff/ > > > Testing > ------- > > Unit tests to test scenarios for inorder processing, out-of-order processing > and commit semantics. > > > Thanks, > > Jagadish Venkatraman > >
