Thanks Jason for the suggestion, that looks good to me too.
Regarding the non-fatal exceptions wrapped as CommitFailed, I would like to
clarify if we would cover all the following cases: 1) timeout, 2) unknown
pid, 3) invalid pid mapping, 4) concurrent transactions?
BTW I think it still makes sense to use an umbrella exception in case in
the future we add more non-fatal cases even though today we only have a few.
Guozhang
On Thu, Jan 28, 2021 at 1:08 PM Boyang Chen <reluctanthero...@gmail.com>
wrote:
> Thanks Jason, I agree with the proposed solution here, will update the KIP.
>
> On Thu, Jan 28, 2021 at 10:52 AM Jason Gustafson <ja...@confluent.io>
> wrote:
>
> > Hi Boyang,
> >
> > It seems like a reasonable suggestion. I wonder if a flag is sufficient
> > though. The current `Callback` documentation treats "fatal" errors from
> the
> > perspective of the individual message that was sent.
> >
> > ```
> > * Non-Retriable exceptions (fatal, the message will
> > never be sent):
> > ```
> >
> > However, we also have fatal errors from the perspective of the
> transaction
> > (e.g. when the producer gets fenced). Perhaps that suggests we need
> > something richer than a boolean flag:
> >
> > At a high level, I think the following cases are possible:
> >
> > - message rejected (e.g. message too large, invalid topic)
> > - delivery failed after retries/delivery timeout (e.g. timeout, crc
> error,
> > not enough replicas)
> > - transaction failed (e.g. producer fenced, invalid transaction state)
> >
> > Perhaps instead we can have a type like the following:
> >
> > class SendFailure {
> > FailureType failureType;
> > Exception cause;
> > }
> >
> > enum FailureType {
> > MESSSAGE_REJECTED, DELIVERY_FAILED, TRANSACTION_FAILED
> > }
> >
> > (Not married to any of these names, just a starting point.)
> >
> > Then we add a new `onCompletion` as you've suggested:
> >
> > default void onCompletion(RecordMetadata metadata, SendFailure failure) {
> > this.onCompletion(metadata, failure.cause());
> > }
> >
> > This would give streams and other applications enough information to know
> > whether the message can be retried and whether the transaction can be
> > aborted.
> >
> > What do you think?
> >
> > -Jason
> >
> >
> > On Wed, Jan 27, 2021 at 9:51 PM Boyang Chen <reluctanthero...@gmail.com>
> > wrote:
> >
> > > Thanks Jason for the thoughts.
> > >
> > > On Wed, Jan 27, 2021 at 11:52 AM Jason Gustafson <ja...@confluent.io>
> > > wrote:
> > >
> > > > Hi Boyang,
> > > >
> > > > Thanks for the iterations here. I think this is something we should
> > have
> > > > done a long time ago. It sounds like there are two API changes here:
> > > >
> > > > 1. We are introducing the `CommitFailedException` to wrap abortable
> > > > errors that are raised from `commitTransaction`. This sounds fine to
> > me.
> > > As
> > > > far as I know, the only case we might need this is when we add
> support
> > to
> > > > let producers recover from coordinator timeouts. Are there any
> others?
> > > >
> > > > I think the purpose here is to ensure non-fatal exceptions are
> unified
> > > under the same
> > > exception umbrella, to make the proceeding to abort any ongoing
> > transaction
> > > much easier.
> > > I don't think `coordinator timeouts` is the only case to recover here,
> > > since we have other
> > > non-fatal exceptions such as UnknownPid.
> > >
> > > 2. We are wrapping non-fatal errors raised from `send` as
> > `KafkaException`.
> > > > The motivation for this is less clear to me and it doesn't look like
> > the
> > > > example from the KIP depends on it. My concern here is compatibility.
> > > > Currently we have the following documentation for the `Callback` API:
> > > >
> > > > ```
> > > > * Non-Retriable exceptions (fatal, the message
> > will
> > > > never be sent):
> > > > *
> > > > * InvalidTopicException
> > > > * OffsetMetadataTooLargeException
> > > > * RecordBatchTooLargeException
> > > > * RecordTooLargeException
> > > > * UnknownServerException
> > > > * UnknownProducerIdException
> > > > * InvalidProducerEpochException
> > > > *
> > > > * Retriable exceptions (transient, may be
> covered
> > > by
> > > > increasing #.retries):
> > > > *
> > > > * CorruptRecordException
> > > > * InvalidMetadataException
> > > > * NotEnoughReplicasAfterAppendException
> > > > * NotEnoughReplicasException
> > > > * OffsetOutOfRangeException
> > > > * TimeoutException
> > > > * UnknownTopicOrPartitionException
> > > > ```
> > > >
> > > > If we wrap all the retriable exceptions documented here as
> > > > `KafkaException`, wouldn't that break any error handling that users
> > might
> > > > already have? it's gonna introduce a compatibility issue.
> > > >
> > > > The original intention was to simplify `send` callback error handling
> > by
> > > doing exception wrapping, as on Streams level
> > > we have to prepare an exhausting list of exceptions to catch as fatal,
> > and
> > > the same lengthy list to catch as
> > > non-fatal. It would be much easier if we got `hints` from the callback.
> > > However,
> > > I agree there is a compatibility concern, what about deprecating the
> > > existing:
> > >
> > > void onCompletion(RecordMetadata metadata, Exception exception)
> > >
> > > and replace it with:
> > >
> > > default void onCompletion(RecordMetadata metadata, Exception exception,
> > > boolean isFatal) {
> > > this.onCompletion(metadata, exception);
> > > }
> > >
> > > to make sure new users get the benefit of understanding the fatality
> > based
> > > on the info presented by the producer?
> > >
> > > Thanks,
> > > > Jason
> > > >
> > > >
> > > > On Sat, Jan 23, 2021 at 3:31 AM Hiringuru <i...@hiringuru.com>
> wrote:
> > > >
> > > > > Why we are receiving all emails kindly remove us from
> > > > > dev@kafka.apache.org we don't want to receive emails anymore.
> > > > >
> > > > > Thanks
> > > > > > On 01/23/2021 4:14 AM Guozhang Wang <wangg...@gmail.com> wrote:
> > > > > >
> > > > > >
> > > > > > Thanks Boyang, yes I think I was confused about the different
> > > handling
> > > > of
> > > > > > two abortTxn calls, and now I get it was not intentional. I
> think I
> > > do
> > > > > not
> > > > > > have more concerns.
> > > > > >
> > > > > > On Fri, Jan 22, 2021 at 1:12 PM Boyang Chen <
> > > > reluctanthero...@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Thanks for the clarification Guozhang, I got your point that we
> > > want
> > > > to
> > > > > > > have a consistent handling of fatal exceptions being thrown
> from
> > > the
> > > > > > > abortTxn. I modified the current template to move the fatal
> > > exception
> > > > > > > try-catch outside of the processing loop to make sure we could
> > get
> > > a
> > > > > chance
> > > > > > > to close consumer/producer modules. Let me know what you think.
> > > > > > >
> > > > > > > Best,
> > > > > > > Boyang
> > > > > > >
> > > > > > > On Fri, Jan 22, 2021 at 11:05 AM Boyang Chen <
> > > > > reluctanthero...@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > My understanding is that abortTransaction would only throw
> when
> > > the
> > > > > > > > producer is in fatal state. For CommitFailed, the producer
> > should
> > > > > still
> > > > > > > be
> > > > > > > > in the abortable error state, so that abortTransaction call
> > would
> > > > not
> > > > > > > throw.
> > > > > > > >
> > > > > > > > On Fri, Jan 22, 2021 at 11:02 AM Guozhang Wang <
> > > wangg...@gmail.com
> > > > >
> > > > > > > wrote:
> > > > > > > >
> > > > > > > >> Or are you going to maintain some internal state such that,
> > the
> > > > > > > >> `abortTransaction` in the catch block would never throw
> again?
> > > > > > > >>
> > > > > > > >> On Fri, Jan 22, 2021 at 11:01 AM Guozhang Wang <
> > > > wangg...@gmail.com>
> > > > > > > >> wrote:
> > > > > > > >>
> > > > > > > >> > Hi Boyang/Jason,
> > > > > > > >> >
> > > > > > > >> > I've also thought about this (i.e. using CommitFailed for
> > all
> > > > > > > >> non-fatal),
> > > > > > > >> > but what I'm pondering is that, in the catch
> (CommitFailed)
> > > > block,
> > > > > > > what
> > > > > > > >> > would happen if the `producer.abortTransaction();` throws
> > > again?
> > > > > > > should
> > > > > > > >> > that be captured as a fatal and cause the client to close
> > > again.
> > > > > > > >> >
> > > > > > > >> > If yes, then naively the pattern would be:
> > > > > > > >> >
> > > > > > > >> > ...
> > > > > > > >> > catch (CommitFailedException e) {
> > > > > > > >> > // Transaction commit failed with abortable error,
> > > user
> > > > > could
> > > > > > > >> reset
> > > > > > > >> > // the application state and resume with a new
> > > > > transaction.
> > > > > > > The
> > > > > > > >> > root
> > > > > > > >> > // cause was wrapped in the thrown exception.
> > > > > > > >> > resetToLastCommittedPositions(consumer);
> > > > > > > >> > try {
> > > > > > > >> > producer.abortTransaction();
> > > > > > > >> > } catch (KafkaException e) {
> > > > > > > >> > producer.close();
> > > > > > > >> > consumer.close();
> > > > > > > >> > throw e;
> > > > > > > >> > }
> > > > > > > >> > } catch (KafkaException e) {
> > > > > > > >> > producer.close();
> > > > > > > >> > consumer.close();
> > > > > > > >> > throw e;
> > > > > > > >> > }
> > > > > > > >> > ...
> > > > > > > >> >
> > > > > > > >> > Guozhang
> > > > > > > >> >
> > > > > > > >> > On Fri, Jan 22, 2021 at 10:47 AM Boyang Chen <
> > > > > > > >> reluctanthero...@gmail.com>
> > > > > > > >> > wrote:
> > > > > > > >> >
> > > > > > > >> >> Hey Guozhang,
> > > > > > > >> >>
> > > > > > > >> >> Jason and I were discussing the new API offline and
> decided
> > > to
> > > > > take
> > > > > > > >> >> another
> > > > > > > >> >> approach. Firstly, the reason not to invent a new API
> with
> > > > > returned
> > > > > > > >> >> boolean
> > > > > > > >> >> flag is for compatibility consideration, since old EOS
> code
> > > > > would not
> > > > > > > >> know
> > > > > > > >> >> that a given transaction commit was failed internally as
> > they
> > > > > don't
> > > > > > > >> listen
> > > > > > > >> >> to the output flag. Our proposed alternative solution is
> to
> > > let
> > > > > > > >> >> *commitTransaction
> > > > > > > >> >> throw CommitFailedException whenever the commit failed
> with
> > > > > non-fatal
> > > > > > > >> >> exception*, so that on the caller side the handling logic
> > > > > becomes:
> > > > > > > >> >>
> > > > > > > >> >> try {
> > > > > > > >> >> if (shouldCommit) {
> > > > > > > >> >> producer.commitTransaction();
> > > > > > > >> >> } else {
> > > > > > > >> >> resetToLastCommittedPositions(consumer);
> > > > > > > >> >> producer.abortTransaction();
> > > > > > > >> >> }
> > > > > > > >> >> } catch (CommitFailedException e) {
> > > > > > > >> >> // Transaction commit failed with abortable
> error,
> > > user
> > > > > could
> > > > > > > >> >> reset
> > > > > > > >> >> // the application state and resume with a new
> > > > > transaction.
> > > > > > > The
> > > > > > > >> >> root
> > > > > > > >> >> // cause was wrapped in the thrown exception.
> > > > > > > >> >> resetToLastCommittedPositions(consumer);
> > > > > > > >> >> producer.abortTransaction();
> > > > > > > >> >> } catch (KafkaException e) {
> > > > > > > >> >> producer.close();
> > > > > > > >> >> consumer.close();
> > > > > > > >> >> throw e;
> > > > > > > >> >> }
> > > > > > > >> >>
> > > > > > > >> >> This approach looks cleaner as all exception types other
> > than
> > > > > > > >> CommitFailed
> > > > > > > >> >> will doom to be fatal, which is very easy to adopt for
> > users.
> > > > In
> > > > > the
> > > > > > > >> >> meantime, we still maintain the commitTxn behavior to
> throw
> > > > > instead
> > > > > > > of
> > > > > > > >> >> silently failing.
> > > > > > > >> >>
> > > > > > > >> >> In addition, we decided to drop the recommendation to
> > handle
> > > > > > > >> >> TimeoutException and leave it to the users to make the
> > call.
> > > > The
> > > > > > > >> downside
> > > > > > > >> >> for blindly calling abortTxn upon timeout is that we
> could
> > > > > result in
> > > > > > > an
> > > > > > > >> >> illegal state when the commit was already successful on
> the
> > > > > broker
> > > > > > > >> >> side. Without a good guarantee on the outcome,
> > > overcomplicating
> > > > > the
> > > > > > > >> >> template should not be encouraged IMHO.
> > > > > > > >> >>
> > > > > > > >> >> Let me know your thoughts on the new approach here, thank
> > > you!
> > > > > > > >> >>
> > > > > > > >> >> Best,
> > > > > > > >> >> Boyang
> > > > > > > >> >>
> > > > > > > >> >> On Tue, Jan 19, 2021 at 11:11 AM Guozhang Wang <
> > > > > wangg...@gmail.com>
> > > > > > > >> >> wrote:
> > > > > > > >> >>
> > > > > > > >> >> > Thanks for your clarification on 2)/3), that makes
> sense.
> > > > > > > >> >> >
> > > > > > > >> >> > On Tue, Jan 19, 2021 at 10:16 AM Boyang Chen <
> > > > > > > >> >> reluctanthero...@gmail.com>
> > > > > > > >> >> > wrote:
> > > > > > > >> >> >
> > > > > > > >> >> > > Thanks for the input Guozhang, replied inline.
> > > > > > > >> >> > >
> > > > > > > >> >> > > On Mon, Jan 18, 2021 at 8:57 PM Guozhang Wang <
> > > > > > > wangg...@gmail.com>
> > > > > > > >> >> > wrote:
> > > > > > > >> >> > >
> > > > > > > >> >> > > > Hello Boyang,
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > Thanks for the updated KIP. I read it again and
> have
> > > the
> > > > > > > >> following
> > > > > > > >> >> > > > thoughts:
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > 0. I'm a bit concerned that if commitTxn does not
> > throw
> > > > any
> > > > > > > >> >> non-fatal
> > > > > > > >> >> > > > exception, and instead we rely on the subsequent
> > > beginTxn
> > > > > call
> > > > > > > to
> > > > > > > >> >> > throw,
> > > > > > > >> >> > > it
> > > > > > > >> >> > > > may violate some callers with a pattern that
> relying
> > on
> > > > > > > >> commitTxn to
> > > > > > > >> >> > > > succeed to make some non-rollback operations. For
> > > > example:
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > beginTxn()
> > > > > > > >> >> > > > // do some read-write on my local DB
> > > > > > > >> >> > > > commitTxn()
> > > > > > > >> >> > > > // if commitTxn succeeds, then commit the DB
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > -------------
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > The issue is that, committing DB is a non-rollback
> > > > > operation,
> > > > > > > and
> > > > > > > >> >> users
> > > > > > > >> >> > > may
> > > > > > > >> >> > > > just rely on commitTxn to return without error to
> > make
> > > > this
> > > > > > > >> >> > non-rollback
> > > > > > > >> >> > > > call. Of course we can just claim this pattern is
> not
> > > > > > > legitimate
> > > > > > > >> >> and is
> > > > > > > >> >> > > not
> > > > > > > >> >> > > > the right way of doing things, but many users may
> > > > naturally
> > > > > > > adopt
> > > > > > > >> >> this
> > > > > > > >> >> > > > pattern.
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > So maybe we should still let commitTxn also throw
> > > > non-fatal
> > > > > > > >> >> exceptions,
> > > > > > > >> >> > > in
> > > > > > > >> >> > > > which case we would then call abortTxn again.
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > But if we do this, the pattern becomes:
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > try {
> > > > > > > >> >> > > > beginTxn()
> > > > > > > >> >> > > > // do something
> > > > > > > >> >> > > > } catch (Exception) {
> > > > > > > >> >> > > > shouldCommit = false;
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > if (shouldCommit) {
> > > > > > > >> >> > > > try {
> > > > > > > >> >> > > > commitTxn()
> > > > > > > >> >> > > > } catch (...) { // enumerate all fatal
> > > > > exceptions
> > > > > > > >> >> > > > shutdown()
> > > > > > > >> >> > > > } catch (KafkaException) {
> > > > > > > >> >> > > > // non-fatal
> > > > > > > >> >> > > > shouldCommit = false;
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > if (!shouldCommit && running()) {
> > > > > > > >> >> > > > try {
> > > > > > > >> >> > > > abortTxn()
> > > > > > > >> >> > > > } catch (KafkaException) {
> > > > > > > >> >> > > > // only throw fatal
> > > > > > > >> >> > > > shutdown()
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > ---------------------
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > Which is much more complicated.
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > Thank makes me think, the alternative we have
> > discussed
> > > > > offline
> > > > > > > >> may
> > > > > > > >> >> be
> > > > > > > >> >> > > > better: let commitTxn() to return a boolean flag.
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > * If it returns true, it means the commit
> succeeded.
> > > > Users
> > > > > can
> > > > > > > >> >> > > comfortably
> > > > > > > >> >> > > > continue and do any external non-rollback
> operations
> > if
> > > > > they
> > > > > > > >> like.
> > > > > > > >> >> > > > * If it returns false, it means the commit failed
> > with
> > > > > > > non-fatal
> > > > > > > >> >> error
> > > > > > > >> >> > > *AND
> > > > > > > >> >> > > > the txn has been aborted*. Users do not need to
> call
> > > > > abortTxn
> > > > > > > >> again.
> > > > > > > >> >> > > > * If it throws, then it means fatal errors. Users
> > > should
> > > > > shut
> > > > > > > >> down
> > > > > > > >> >> the
> > > > > > > >> >> > > > client.
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > In this case, the pattern becomes:
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > try {
> > > > > > > >> >> > > > beginTxn()
> > > > > > > >> >> > > > // do something
> > > > > > > >> >> > > > } catch (Exception) {
> > > > > > > >> >> > > > shouldCommit = false;
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > try {
> > > > > > > >> >> > > > if (shouldCommit) {
> > > > > > > >> >> > > > commitSucceeded = commitTxn()
> > > > > > > >> >> > > > } else {
> > > > > > > >> >> > > > // reset offsets, rollback operations, etc
> > > > > > > >> >> > > > abortTxn()
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > > } catch (KafkaException) {
> > > > > > > >> >> > > > // only throw fatal
> > > > > > > >> >> > > > shutdown()
> > > > > > > >> >> > > > }
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > if (commitSucceeded)
> > > > > > > >> >> > > > // do other non-rollbackable things
> > > > > > > >> >> > > > else
> > > > > > > >> >> > > > // reset offsets, rollback operations, etc
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > -------------------------
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > Of course, if we want to have better visibility
> into
> > > what
> > > > > > > caused
> > > > > > > >> the
> > > > > > > >> >> > > commit
> > > > > > > >> >> > > > to fail and txn to abort. We can let the return
> type
> > be
> > > > an
> > > > > enum
> > > > > > > >> >> instead
> > > > > > > >> >> > > of
> > > > > > > >> >> > > > a flag. But my main idea is to still let the
> > commitTxn
> > > be
> > > > > the
> > > > > > > >> final
> > > > > > > >> >> > point
> > > > > > > >> >> > > > users can tell whether this txn succeeded or not,
> > > instead
> > > > > of
> > > > > > > >> >> relying on
> > > > > > > >> >> > > the
> > > > > > > >> >> > > > next beginTxn() call.
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > I agree that adding a boolean flag is indeed useful
> > in
> > > > this
> > > > > > > case.
> > > > > > > >> >> Will
> > > > > > > >> >> > > update the KIP.
> > > > > > > >> >> > >
> > > > > > > >> >> > > 1. Re: "while maintaining the behavior to throw fatal
> > > > > exception
> > > > > > > in
> > > > > > > >> >> raw"
> > > > > > > >> >> > not
> > > > > > > >> >> > > > sure what do you mean by "throw" here. Are you
> > > proposing
> > > > > the
> > > > > > > >> >> callback
> > > > > > > >> >> > > would
> > > > > > > >> >> > > > *pass* (not throw) in any fatal exceptions when
> > > triggered
> > > > > > > without
> > > > > > > >> >> > > wrapping?
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > Yes, I want to say *pass*, the benefit is to make
> the
> > > end
> > > > > > > user's
> > > > > > > >> >> > > expectation consistent
> > > > > > > >> >> > > regarding exception handling.
> > > > > > > >> >> > >
> > > > > > > >> >> > >
> > > > > > > >> >> > > > 2. I'm not sure I understand the claim regarding
> the
> > > > > callback
> > > > > > > >> that
> > > > > > > >> >> "In
> > > > > > > >> >> > > EOS
> > > > > > > >> >> > > > setup, it is not required to handle the exception".
> > Are
> > > > you
> > > > > > > >> >> proposing
> > > > > > > >> >> > > that,
> > > > > > > >> >> > > > e.g. in Streams, we do not try to handle any
> > exceptions
> > > > if
> > > > > EOS
> > > > > > > is
> > > > > > > >> >> > enabled
> > > > > > > >> >> > > > in the callback anymore, but just let commitTxn()
> > > itself
> > > > to
> > > > > > > fail
> > > > > > > >> to
> > > > > > > >> >> be
> > > > > > > >> >> > > > notified about the problem? Personally I think in
> > > Streams
> > > > > we
> > > > > > > >> should
> > > > > > > >> >> > just
> > > > > > > >> >> > > > make the handling logic of the callback to be
> > > consistent
> > > > > > > >> regardless
> > > > > > > >> >> of
> > > > > > > >> >> > > the
> > > > > > > >> >> > > > EOS settings (today we have different logic
> depending
> > > on
> > > > > this
> > > > > > > >> logic,
> > > > > > > >> >> > > which
> > > > > > > >> >> > > > I think could be unified as well).
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > My idea originates from the claim on send API:
> > > > > > > >> >> > > "When used as part of a transaction, it is not
> > necessary
> > > to
> > > > > > > define
> > > > > > > >> a
> > > > > > > >> >> > > callback or check the result of the future in order
> to
> > > > > detect
> > > > > > > >> errors
> > > > > > > >> >> > from
> > > > > > > >> >> > > <code>send</code>. "
> > > > > > > >> >> > > My understanding is that for EOS, the exception will
> be
> > > > > detected
> > > > > > > by
> > > > > > > >> >> > calling
> > > > > > > >> >> > > transactional APIs either way, so it is a duplicate
> > > > handling
> > > > > to
> > > > > > > >> track
> > > > > > > >> >> > > all the sendExceptions in RecordCollector. However, I
> > > > looked
> > > > > up
> > > > > > > >> >> > > sendException is being used today as follow:
> > > > > > > >> >> > >
> > > > > > > >> >> > > 1. Pass to "ProductionExceptionHandler" for any
> default
> > > or
> > > > > > > >> customized
> > > > > > > >> >> > > exception handler to handle
> > > > > > > >> >> > > 2. Stop collecting offset info or new exceptions
> > > > > > > >> >> > > 3. Check and rethrow exceptions in close(), flush()
> or
> > > new
> > > > > send()
> > > > > > > >> >> calls
> > > > > > > >> >> > >
> > > > > > > >> >> > > To my understanding, we should still honor the
> > commitment
> > > > to
> > > > > #1
> > > > > > > for
> > > > > > > >> >> any
> > > > > > > >> >> > > user customized implementation. The #2 does not
> really
> > > > > affect our
> > > > > > > >> >> > decision
> > > > > > > >> >> > > upon EOS. The #3 here is still valuable as it could
> > help
> > > us
> > > > > fail
> > > > > > > >> fast
> > > > > > > >> >> in
> > > > > > > >> >> > > new send() instead of waiting to later stage of
> > > processing.
> > > > > In
> > > > > > > that
> > > > > > > >> >> > sense,
> > > > > > > >> >> > > I agree we should continue to record send exceptions
> > even
> > > > > under
> > > > > > > EOS
> > > > > > > >> >> case
> > > > > > > >> >> > to
> > > > > > > >> >> > > ensure the strength of stream side Producer logic. On
> > the
> > > > > safer
> > > > > > > >> side,
> > > > > > > >> >> we
> > > > > > > >> >> > no
> > > > > > > >> >> > > longer need to wrap certain fatal exceptions like
> > > > > ProducerFenced
> > > > > > > as
> > > > > > > >> >> > > TaskMigrated, since they should not crash the stream
> > > thread
> > > > > if
> > > > > > > >> thrown
> > > > > > > >> >> in
> > > > > > > >> >> > > raw format, once we adopt the new processing model in
> > the
> > > > > send
> > > > > > > >> phase.
> > > > > > > >> >> > >
> > > > > > > >> >> > >
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > Guozhang
> > > > > > > >> >> > > >
> > > > > > > >> >> > > >
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > On Thu, Dec 17, 2020 at 8:42 PM Boyang Chen <
> > > > > > > >> >> > reluctanthero...@gmail.com>
> > > > > > > >> >> > > > wrote:
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > > Thanks for everyone's feedback so far. I have
> > > polished
> > > > > the
> > > > > > > KIP
> > > > > > > >> >> after
> > > > > > > >> >> > > > > offline discussion with some folks working on EOS
> > to
> > > > > make the
> > > > > > > >> >> > exception
> > > > > > > >> >> > > > > handling more lightweight. The essential change
> is
> > > that
> > > > > we
> > > > > > > are
> > > > > > > >> not
> > > > > > > >> >> > > > > inventing a new intermediate exception type, but
> > > > instead
> > > > > > > >> >> separating a
> > > > > > > >> >> > > > full
> > > > > > > >> >> > > > > transaction into two phases:
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > > > 1. The data transmission phase
> > > > > > > >> >> > > > > 2. The commit phase
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > > > This way for any exception thrown from phase 1,
> > will
> > > be
> > > > > an
> > > > > > > >> >> indicator
> > > > > > > >> >> > in
> > > > > > > >> >> > > > > phase 2 whether we should do commit or abort, and
> > > from
> > > > > now on
> > > > > > > >> >> > > > > `commitTransaction` should only throw fatal
> > > exceptions,
> > > > > > > >> similar to
> > > > > > > >> >> > > > > `abortTransaction`, so that any KafkaException
> > caught
> > > > in
> > > > > the
> > > > > > > >> >> commit
> > > > > > > >> >> > > phase
> > > > > > > >> >> > > > > will be definitely fatal to crash the app. For
> more
> > > > > advanced
> > > > > > > >> users
> > > > > > > >> >> > such
> > > > > > > >> >> > > > as
> > > > > > > >> >> > > > > Streams, we have the ability to further wrap
> > selected
> > > > > types
> > > > > > > of
> > > > > > > >> >> fatal
> > > > > > > >> >> > > > > exceptions to trigger task migration if
> necessary.
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > > > More details in the KIP, feel free to take
> another
> > > > look,
> > > > > > > >> thanks!
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > > > On Thu, Dec 17, 2020 at 8:36 PM Boyang Chen <
> > > > > > > >> >> > > reluctanthero...@gmail.com>
> > > > > > > >> >> > > > > wrote:
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > > > > Thanks Bruno for the feedback.
> > > > > > > >> >> > > > > >
> > > > > > > >> >> > > > > > On Mon, Dec 7, 2020 at 5:26 AM Bruno Cadonna <
> > > > > > > >> >> br...@confluent.io>
> > > > > > > >> >> > > > wrote:
> > > > > > > >> >> > > > > >
> > > > > > > >> >> > > > > >> Thanks Boyang for the KIP!
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> Like Matthias, I do also not know the producer
> > > > > internal
> > > > > > > well
> > > > > > > >> >> > enough
> > > > > > > >> >> > > to
> > > > > > > >> >> > > > > >> comment on the categorization. However, I
> think
> > > > > having a
> > > > > > > >> super
> > > > > > > >> >> > > > exception
> > > > > > > >> >> > > > > >> (e.g. RetriableException) that encodes if an
> > > > > exception is
> > > > > > > >> >> fatal
> > > > > > > >> >> > or
> > > > > > > >> >> > > > not
> > > > > > > >> >> > > > > >> is cleaner, better understandable and less
> > > > > error-prone,
> > > > > > > >> because
> > > > > > > >> >> > > > ideally
> > > > > > > >> >> > > > > >> when you add a new non-fatal exception in
> future
> > > you
> > > > > just
> > > > > > > >> need
> > > > > > > >> >> to
> > > > > > > >> >> > > > think
> > > > > > > >> >> > > > > >> about letting it inherit from the super
> > exception
> > > > and
> > > > > all
> > > > > > > >> the
> > > > > > > >> >> rest
> > > > > > > >> >> > > of
> > > > > > > >> >> > > > > >> the code will just behave correctly without
> the
> > > need
> > > > > to
> > > > > > > wrap
> > > > > > > >> >> the
> > > > > > > >> >> > new
> > > > > > > >> >> > > > > >> exception into another exception each time it
> is
> > > > > thrown
> > > > > > > >> (maybe
> > > > > > > >> >> it
> > > > > > > >> >> > is
> > > > > > > >> >> > > > > >> thrown at different location in the code).
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> As far as I understand the following statement
> > > from
> > > > > your
> > > > > > > >> >> previous
> > > > > > > >> >> > > > e-mail
> > > > > > > >> >> > > > > >> is the reason that currently such a super
> > > exception
> > > > > is not
> > > > > > > >> >> > possible:
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> "Right now we have RetriableException type, if
> > we
> > > > are
> > > > > > > going
> > > > > > > >> to
> > > > > > > >> >> > add a
> > > > > > > >> >> > > > > >> `ProducerRetriableException` type, we have to
> > put
> > > > > this new
> > > > > > > >> >> > interface
> > > > > > > >> >> > > > as
> > > > > > > >> >> > > > > >> the parent of the RetriableException, because
> > not
> > > > all
> > > > > > > thrown
> > > > > > > >> >> > > non-fatal
> > > > > > > >> >> > > > > >> exceptions are `retriable` in general for
> > > producer"
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> In the list of exceptions in your KIP, I found
> > > > > non-fatal
> > > > > > > >> >> > exceptions
> > > > > > > >> >> > > > that
> > > > > > > >> >> > > > > >> do not inherit from RetriableException. I
> guess
> > > > those
> > > > > are
> > > > > > > >> the
> > > > > > > >> >> ones
> > > > > > > >> >> > > you
> > > > > > > >> >> > > > > >> are referring to in your statement:
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> InvalidProducerEpochException
> > > > > > > >> >> > > > > >> InvalidPidMappingException
> > > > > > > >> >> > > > > >> TransactionAbortedException
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> All of those exceptions are non-fatal and do
> not
> > > > > inherit
> > > > > > > >> from
> > > > > > > >> >> > > > > >> RetriableException. Is there a reason for
> that?
> > If
> > > > > they
> > > > > > > >> >> depended
> > > > > > > >> >> > > from
> > > > > > > >> >> > > > > >> RetriableException we would be a bit closer
> to a
> > > > super
> > > > > > > >> >> exception I
> > > > > > > >> >> > > > > >> mention above.
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> The reason is that sender may catch those
> > > exceptions
> > > > > in
> > > > > > > the
> > > > > > > >> >> > > > > > ProduceResponse, and it currently does infinite
> > > > > > > >> >> > > > > > retries on RetriableException. To make sure we
> > > could
> > > > > > > trigger
> > > > > > > >> the
> > > > > > > >> >> > > > > > abortTransaction() by catching non-fatal thrown
> > > > > > > >> >> > > > > > exceptions and reinitialize the txn state, we
> > chose
> > > > > not to
> > > > > > > >> let
> > > > > > > >> >> > those
> > > > > > > >> >> > > > > > exceptions inherit RetriableException so that
> > > > > > > >> >> > > > > > they won't cause infinite retry on sender.
> > > > > > > >> >> > > > > >
> > > > > > > >> >> > > > > >
> > > > > > > >> >> > > > > >> With OutOfOrderSequenceException and
> > > > > > > >> >> UnknownProducerIdException, I
> > > > > > > >> >> > > > think
> > > > > > > >> >> > > > > >> to understand that their fatality depends on
> the
> > > > type
> > > > > > > (i.e.
> > > > > > > >> >> > > > > >> configuration) of the producer. That makes it
> > > > > difficult to
> > > > > > > >> >> have a
> > > > > > > >> >> > > > super
> > > > > > > >> >> > > > > >> exception that encodes the retriability as
> > > mentioned
> > > > > > > above.
> > > > > > > >> >> Would
> > > > > > > >> >> > it
> > > > > > > >> >> > > > be
> > > > > > > >> >> > > > > >> possible to introduce exceptions that inherit
> > from
> > > > > > > >> >> > > RetriableException
> > > > > > > >> >> > > > > >> and that are thrown when those exceptions are
> > > caught
> > > > > from
> > > > > > > >> the
> > > > > > > >> >> > > brokers
> > > > > > > >> >> > > > > >> and the type of the producer is such that the
> > > > > exceptions
> > > > > > > are
> > > > > > > >> >> > > > retriable?
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> Yea, I think in general the exception type
> > mixing
> > > is
> > > > > > > >> difficult
> > > > > > > >> >> to
> > > > > > > >> >> > > get
> > > > > > > >> >> > > > > > them all right. I have already proposed another
> > > > > solution
> > > > > > > >> based
> > > > > > > >> >> on
> > > > > > > >> >> > my
> > > > > > > >> >> > > > > > offline discussion with some folks working on
> EOS
> > > > > > > >> >> > > > > > to make the handling more straightforward for
> end
> > > > users
> > > > > > > >> without
> > > > > > > >> >> the
> > > > > > > >> >> > > > need
> > > > > > > >> >> > > > > > to distinguish exception fatality.
> > > > > > > >> >> > > > > >
> > > > > > > >> >> > > > > >> Best,
> > > > > > > >> >> > > > > >> Bruno
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >> On 04.12.20 19:34, Guozhang Wang wrote:
> > > > > > > >> >> > > > > >> > Thanks Boyang for the proposal! I made a
> pass
> > > over
> > > > > the
> > > > > > > >> list
> > > > > > > >> >> and
> > > > > > > >> >> > > here
> > > > > > > >> >> > > > > are
> > > > > > > >> >> > > > > >> > some thoughts:
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > 0) Although this is not part of the public
> > API,
> > > I
> > > > > think
> > > > > > > we
> > > > > > > >> >> > should
> > > > > > > >> >> > > > make
> > > > > > > >> >> > > > > >> sure
> > > > > > > >> >> > > > > >> > that the suggested pattern (i.e. user can
> > always
> > > > > call
> > > > > > > >> >> abortTxn()
> > > > > > > >> >> > > > when
> > > > > > > >> >> > > > > >> > handling non-fatal errors) are indeed
> > supported.
> > > > > E.g. if
> > > > > > > >> the
> > > > > > > >> >> txn
> > > > > > > >> >> > > is
> > > > > > > >> >> > > > > >> already
> > > > > > > >> >> > > > > >> > aborted by the broker side, then users can
> > still
> > > > > call
> > > > > > > >> >> abortTxn
> > > > > > > >> >> > > which
> > > > > > > >> >> > > > > >> would
> > > > > > > >> >> > > > > >> > not throw another exception but just be
> > treated
> > > > as a
> > > > > > > >> no-op.
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > 1) *ConcurrentTransactionsException*: I
> think
> > > this
> > > > > error
> > > > > > > >> can
> > > > > > > >> >> > also
> > > > > > > >> >> > > be
> > > > > > > >> >> > > > > >> > returned but not documented yet. This should
> > be
> > > a
> > > > > > > >> non-fatal
> > > > > > > >> >> > error.
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > 2) *InvalidTxnStateException*: this error is
> > > > > returned
> > > > > > > from
> > > > > > > >> >> > broker
> > > > > > > >> >> > > > when
> > > > > > > >> >> > > > > >> txn
> > > > > > > >> >> > > > > >> > state transition failed (e.g. it is trying
> to
> > > > > transit to
> > > > > > > >> >> > > > > complete-commit
> > > > > > > >> >> > > > > >> > while the current state is not
> > prepare-commit).
> > > > This
> > > > > > > error
> > > > > > > >> >> could
> > > > > > > >> >> > > > > >> indicates
> > > > > > > >> >> > > > > >> > a bug on the client internal code or the
> > broker
> > > > > code,
> > > > > > > OR a
> > > > > > > >> >> user
> > > > > > > >> >> > > > error
> > > > > > > >> >> > > > > >> --- a
> > > > > > > >> >> > > > > >> > similar error is
> > > ConcurrentTransactionsException,
> > > > > i.e.
> > > > > > > if
> > > > > > > >> >> Kafka
> > > > > > > >> >> > is
> > > > > > > >> >> > > > > >> bug-free
> > > > > > > >> >> > > > > >> > these exceptions would only be returned if
> > users
> > > > > try to
> > > > > > > do
> > > > > > > >> >> > > something
> > > > > > > >> >> > > > > >> wrong,
> > > > > > > >> >> > > > > >> > e.g. calling abortTxn right after a
> commitTxn,
> > > > etc.
> > > > > So
> > > > > > > I'm
> > > > > > > >> >> > > thinking
> > > > > > > >> >> > > > it
> > > > > > > >> >> > > > > >> > should be a non-fatal error instead of a
> fatal
> > > > > error,
> > > > > > > >> wdyt?
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > 3) *KafkaException*: case i "indicates fatal
> > > > > > > transactional
> > > > > > > >> >> > > sequence
> > > > > > > >> >> > > > > >> > (Fatal)", this is a bit conflicting with the
> > > > > > > >> >> > > > *OutOfSequenceException*
> > > > > > > >> >> > > > > >> that
> > > > > > > >> >> > > > > >> > is treated as non-fatal. I guess your
> proposal
> > > is
> > > > > that
> > > > > > > >> >> > > > > >> > OutOfOrderSequenceException would be treated
> > > > either
> > > > > as
> > > > > > > >> fatal
> > > > > > > >> >> > with
> > > > > > > >> >> > > > > >> > transactional producer, or non-fatal with
> > > > idempotent
> > > > > > > >> >> producer,
> > > > > > > >> >> > is
> > > > > > > >> >> > > > that
> > > > > > > >> >> > > > > >> > right? If the producer is only configured
> with
> > > > > > > idempotency
> > > > > > > >> >> but
> > > > > > > >> >> > not
> > > > > > > >> >> > > > > >> > transaction, then throwing a
> > > > > > > >> >> TransactionStateCorruptedException
> > > > > > > >> >> > > for
> > > > > > > >> >> > > > > >> > non-fatal errors would be confusing since
> > users
> > > > are
> > > > > not
> > > > > > > >> using
> > > > > > > >> >> > > > > >> transactions
> > > > > > > >> >> > > > > >> > at all.. So I suggest we always throw
> > > > > > > >> OutOfSequenceException
> > > > > > > >> >> > as-is
> > > > > > > >> >> > > > > (i.e.
> > > > > > > >> >> > > > > >> > not wrapped) no matter how the producer is
> > > > > configured,
> > > > > > > and
> > > > > > > >> >> let
> > > > > > > >> >> > the
> > > > > > > >> >> > > > > >> caller
> > > > > > > >> >> > > > > >> > decide how to handle it based on whether it
> is
> > > > only
> > > > > > > >> >> idempotent
> > > > > > > >> >> > or
> > > > > > > >> >> > > > > >> > transactional itself.
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > 4) Besides all the txn APIs, the `send()`
> > > > callback /
> > > > > > > >> future
> > > > > > > >> >> can
> > > > > > > >> >> > > also
> > > > > > > >> >> > > > > >> throw
> > > > > > > >> >> > > > > >> > txn-related exceptions, I think this KIP
> > should
> > > > also
> > > > > > > cover
> > > > > > > >> >> this
> > > > > > > >> >> > > API
> > > > > > > >> >> > > > as
> > > > > > > >> >> > > > > >> well?
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > 5) This is related to 1/2) above: sometimes
> > > those
> > > > > > > >> non-fatal
> > > > > > > >> >> > errors
> > > > > > > >> >> > > > > like
> > > > > > > >> >> > > > > >> > ConcurrentTxn or InvalidTxnState are not due
> > to
> > > > the
> > > > > > > state
> > > > > > > >> >> being
> > > > > > > >> >> > > > > >> corrupted
> > > > > > > >> >> > > > > >> > at the broker side, but maybe users are
> doing
> > > > > something
> > > > > > > >> >> wrong.
> > > > > > > >> >> > So
> > > > > > > >> >> > > > I'm
> > > > > > > >> >> > > > > >> > wondering if we should further distinguish
> > those
> > > > > > > non-fatal
> > > > > > > >> >> > errors
> > > > > > > >> >> > > > > >> between
> > > > > > > >> >> > > > > >> > a) those that are caused by Kafka itself,
> > e.g. a
> > > > > broker
> > > > > > > >> timed
> > > > > > > >> >> > out
> > > > > > > >> >> > > > and
> > > > > > > >> >> > > > > >> > aborted a txn and later an endTxn request is
> > > > > received,
> > > > > > > >> and b)
> > > > > > > >> >> > the
> > > > > > > >> >> > > > > user's
> > > > > > > >> >> > > > > >> > API call pattern is incorrect, causing the
> > > request
> > > > > to be
> > > > > > > >> >> > rejected
> > > > > > > >> >> > > > with
> > > > > > > >> >> > > > > >> an
> > > > > > > >> >> > > > > >> > error code from the broker.
> > > > > > > >> >> *TransactionStateCorruptedException*
> > > > > > > >> >> > > > feels
> > > > > > > >> >> > > > > >> to
> > > > > > > >> >> > > > > >> > me more like for case a), but not case b).
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > Guozhang
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> > On Wed, Dec 2, 2020 at 4:50 PM Boyang Chen <
> > > > > > > >> >> > > > > reluctanthero...@gmail.com>
> > > > > > > >> >> > > > > >> > wrote:
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> >> Thanks Matthias, I think your proposal
> makes
> > > > sense
> > > > > as
> > > > > > > >> well,
> > > > > > > >> >> on
> > > > > > > >> >> > > the
> > > > > > > >> >> > > > > pro
> > > > > > > >> >> > > > > >> side
> > > > > > > >> >> > > > > >> >> we could have a universally agreed
> exception
> > > type
> > > > > to be
> > > > > > > >> >> caught
> > > > > > > >> >> > by
> > > > > > > >> >> > > > the
> > > > > > > >> >> > > > > >> user,
> > > > > > > >> >> > > > > >> >> without having an extra layer on top of the
> > > > actual
> > > > > > > >> >> exceptions.
> > > > > > > >> >> > I
> > > > > > > >> >> > > > > could
> > > > > > > >> >> > > > > >> see
> > > > > > > >> >> > > > > >> >> some issue on downsides:
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >> >> 1. The exception hierarchy will be more
> > > complex.
> > > > > Right
> > > > > > > >> now
> > > > > > > >> >> we
> > > > > > > >> >> > > have
> > > > > > > >> >> > > > > >> >> RetriableException type, if we are going to
> > > add a
> > > > > > > >> >> > > > > >> >> `ProducerRetriableException` type, we have
> to
> > > put
> > > > > this
> > > > > > > >> new
> > > > > > > >> >> > > > interface
> > > > > > > >> >> > > > > >> as the
> > > > > > > >> >> > > > > >> >> parent of the RetriableException, because
> not
> > > all
> > > > > > > thrown
> > > > > > > >> >> > > non-fatal
> > > > > > > >> >> > > > > >> >> exceptions are `retriable` in general for
> > > > > producer, for
> > > > > > > >> >> example
> > > > > > > >> >> > > > > >> >> <
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > >
> > > > > > > >> >> > >
> > > > > > > >> >> >
> > > > > > > >> >>
> > > > > > > >>
> > > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/e275742f850af4a1b79b0d1bd1ac9a1d2e89c64e/clients/src/main/java/org/apache/kafka/clients/producer/internals/Sender.java#L745
> > > > > > > >> >> > > > > >> >>> .
> > > > > > > >> >> > > > > >> >> We could have an empty interface
> > > > > > > >> >> `ProducerRetriableException`
> > > > > > > >> >> > to
> > > > > > > >> >> > > > let
> > > > > > > >> >> > > > > >> all
> > > > > > > >> >> > > > > >> >> the thrown exceptions implement for sure,
> but
> > > > it's
> > > > > a
> > > > > > > bit
> > > > > > > >> >> > > unorthodox
> > > > > > > >> >> > > > > in
> > > > > > > >> >> > > > > >> the
> > > > > > > >> >> > > > > >> >> way we deal with exceptions in general.
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >> >> 2. There are cases where we throw a
> > > > KafkaException
> > > > > > > >> wrapping
> > > > > > > >> >> > > another
> > > > > > > >> >> > > > > >> >> KafkaException as either fatal or
> non-fatal.
> > If
> > > > we
> > > > > use
> > > > > > > an
> > > > > > > >> >> > > interface
> > > > > > > >> >> > > > > to
> > > > > > > >> >> > > > > >> >> solve #1, it is also required to implement
> > > > another
> > > > > > > >> bloated
> > > > > > > >> >> > > > exception
> > > > > > > >> >> > > > > >> class
> > > > > > > >> >> > > > > >> >> which could replace KafkaException type, as
> > we
> > > > > couldn't
> > > > > > > >> mark
> > > > > > > >> >> > > > > >> KafkaException
> > > > > > > >> >> > > > > >> >> as retriable for sure.
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >> >> 3. In terms of the encapsulation, wrapping
> > > means
> > > > we
> > > > > > > could
> > > > > > > >> >> limit
> > > > > > > >> >> > > the
> > > > > > > >> >> > > > > >> scope
> > > > > > > >> >> > > > > >> >> of affection to the producer only, which is
> > > > > important
> > > > > > > >> since
> > > > > > > >> >> we
> > > > > > > >> >> > > > don't
> > > > > > > >> >> > > > > >> want
> > > > > > > >> >> > > > > >> >> shared exception types to implement a
> > > > > producer-related
> > > > > > > >> >> > interface,
> > > > > > > >> >> > > > > such
> > > > > > > >> >> > > > > >> >> as UnknownTopicOrPartitionException.
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >> >> Best,
> > > > > > > >> >> > > > > >> >> Boyang
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >> >> On Wed, Dec 2, 2020 at 3:38 PM Matthias J.
> > Sax
> > > <
> > > > > > > >> >> > mj...@apache.org
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > > >> wrote:
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >> >>> Thanks for the KIP Boyang!
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>> Overall, categorizing exceptions makes a
> lot
> > > of
> > > > > sense.
> > > > > > > >> As I
> > > > > > > >> >> > > don't
> > > > > > > >> >> > > > > know
> > > > > > > >> >> > > > > >> >>> the producer internals well enough, I
> cannot
> > > > > comment
> > > > > > > on
> > > > > > > >> the
> > > > > > > >> >> > > > > >> >>> categorization in detail though.
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>> What I am wondering is, if we should
> > introduce
> > > > an
> > > > > > > >> exception
> > > > > > > >> >> > > > > interface
> > > > > > > >> >> > > > > >> >>> that non-fatal exception would implement
> > > instead
> > > > > of
> > > > > > > >> >> creating a
> > > > > > > >> >> > > new
> > > > > > > >> >> > > > > >> class
> > > > > > > >> >> > > > > >> >>> that will wrap non-fatal exceptions? What
> > > would
> > > > > be the
> > > > > > > >> >> > pros/cons
> > > > > > > >> >> > > > for
> > > > > > > >> >> > > > > >> >>> both designs?
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>> -Matthias
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>> On 12/2/20 11:35 AM, Boyang Chen wrote:
> > > > > > > >> >> > > > > >> >>>> Hey there,
> > > > > > > >> >> > > > > >> >>>>
> > > > > > > >> >> > > > > >> >>>> I would like to start a discussion thread
> > for
> > > > > > > KIP-691:
> > > > > > > >> >> > > > > >> >>>>
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > >
> > > > > > > >> >> > >
> > > > > > > >> >> >
> > > > > > > >> >>
> > > > > > > >>
> > > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-691%3A+Enhance+Transactional+Producer+Exception+Handling
> > > > > > > >> >> > > > > >> >>>>
> > > > > > > >> >> > > > > >> >>>> The KIP is aiming to simplify the
> exception
> > > > > handling
> > > > > > > >> logic
> > > > > > > >> >> > for
> > > > > > > >> >> > > > > >> >>>> transactional Producer users by
> classifying
> > > > > fatal and
> > > > > > > >> >> > non-fatal
> > > > > > > >> >> > > > > >> >>> exceptions
> > > > > > > >> >> > > > > >> >>>> and throw them correspondingly for easier
> > > catch
> > > > > and
> > > > > > > >> retry.
> > > > > > > >> >> > Let
> > > > > > > >> >> > > me
> > > > > > > >> >> > > > > >> know
> > > > > > > >> >> > > > > >> >>> what
> > > > > > > >> >> > > > > >> >>>> you think.
> > > > > > > >> >> > > > > >> >>>>
> > > > > > > >> >> > > > > >> >>>> Best,
> > > > > > > >> >> > > > > >> >>>> Boyang
> > > > > > > >> >> > > > > >> >>>>
> > > > > > > >> >> > > > > >> >>>
> > > > > > > >> >> > > > > >> >>
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >> >
> > > > > > > >> >> > > > > >>
> > > > > > > >> >> > > > > >
> > > > > > > >> >> > > > >
> > > > > > > >> >> > > >
> > > > > > > >> >> > > >
> > > > > > > >> >> > > > --
> > > > > > > >> >> > > > -- Guozhang
> > > > > > > >> >> > > >
> > > > > > > >> >> > >
> > > > > > > >> >> >
> > > > > > > >> >> >
> > > > > > > >> >> > --
> > > > > > > >> >> > -- Guozhang
> > > > > > > >> >> >
> > > > > > > >> >>
> > > > > > > >> >
> > > > > > > >> >
> > > > > > > >> > --
> > > > > > > >> > -- Guozhang
> > > > > > > >> >
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> --
> > > > > > > >> -- Guozhang
> > > > > > > >>
> > > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > > > --
> > > > > > -- Guozhang
> > > > >
> > > >
> > >
> >
>
--
-- Guozhang
