Hi, Justine, Thanks for the reply.
120. If the broker sends TV Y for the finalized version in ApiVersionResponse, but the client doesn't support Y, how does the broker know the TV that the client supports? Jun On Wed, Jul 10, 2024 at 2:29 PM Justine Olshan <jols...@confluent.io.invalid> wrote: > Hey Jun, > > No worries. Work on this KIP has been blocked for a bit anyways -- catching > up and rereading what I wrote :) > > 120. ClientTransactionProtocolVersion is the transaction version as defined > by the highest transaction version (feature version value) supported by the > client and the server. This works by the broker sending an > ApiVersionsRequest to the client with the finalized version. Assuming > kip-890 part 2 is enabled by transaction version Y, if this request > contains finalized version Y and the client has the logic to set this > field, it will set Y. If the server has Y - 1 (kip 890 part 2 not enable) > the client will send Y - 1, even though the client has the ability to > support kip-890 part 2. > > 121. You are correct that this is not needed. However, currently that field > is already being set in memory -- just not written to disk. I think it is > ok to write it to disk though. Let me know if you think otherwise. > > Justine > > On Wed, Jul 10, 2024 at 2:16 PM Jun Rao <j...@confluent.io.invalid> wrote: > > > Hi, Justine, > > > > Thanks for the update and sorry for the late reply. > > > > 120. I am wondering what value is used for > > ClientTransactionProtocolVersion. Is it the version of the EndTxnRequest? > > > > 121. Earlier, you made the change to set lastProducerId in PREPARE to > > indicate that the marker is written for the new client. With the new > > ClientTransactionProtocolVersion field, it seems this is no longer > > necessary. > > > > Jun > > > > On Thu, Mar 28, 2024 at 2:41 PM Justine Olshan > > <jols...@confluent.io.invalid> > > wrote: > > > > > Hi there -- another update! > > > > > > When looking into the implementation for the safe epoch bumps I > realized > > > that we are already populating previousProducerID in memory as part of > > > KIP-360. > > > If we are to start using flexible fields, it is better to always use > this > > > information and have an explicit (tagged) field to indicate whether the > > > client supports KIP-890 part 2. > > > > > > I've included the extra field and how it is set in the KIP. I've also > > > updated the KIP to explain that we will be setting the tagged fields > when > > > they are available for all transitions. > > > > > > Finally, I added clearer text about the transaction protocol versions > > > included with this KIP. 1 for flexible transaction state records and 2 > > for > > > KIP-890 part 2 enablement. > > > > > > Justine > > > > > > On Mon, Mar 18, 2024 at 6:39 PM Justine Olshan <jols...@confluent.io> > > > wrote: > > > > > > > Hey there -- small update to the KIP, > > > > > > > > The KIP mentioned introducing ABORTABLE_ERROR and bumping > > TxnOffsetCommit > > > > and Produce requests. I've changed the name in the KIP to > > > > ABORTABLE_TRANSACTION and the corresponding exception > > > > AbortableTransactionException to match the pattern we had for other > > > errors. > > > > I also mentioned bumping all 6 transactional APIs so we can future > > > > proof/support the error on the client going forward. If a future > change > > > > wants to have an error scenario that requires us to abort the > > > transaction, > > > > we can rely on the 3.8+ clients to support it. We ran into issues > > finding > > > > good/generic error codes that older clients could support while > working > > > on > > > > this KIP, so this should help in the future. > > > > > > > > The features discussion is still ongoing in KIP-1022. Will update > again > > > > here when that concludes. > > > > > > > > Justine > > > > > > > > On Tue, Feb 6, 2024 at 8:39 AM Justine Olshan <jols...@confluent.io> > > > > wrote: > > > > > > > >> I don't think AddPartitions is a good example since we currenly > don't > > > >> gate the version on TV or MV. (We only set a different flag > depending > > on > > > >> the TV) > > > >> > > > >> Even if we did want to gate it on TV, I think the idea is to move > away > > > >> from MV gating inter broker protocols. Ideally we can get to a state > > > where > > > >> MV is just used for metadata changes. > > > >> > > > >> I think some of this discussion might fit more with the feature > > version > > > >> KIP, so I can try to open that up soon. Until we settle that, some > of > > > the > > > >> work in KIP-890 is blocked. > > > >> > > > >> Justine > > > >> > > > >> On Mon, Feb 5, 2024 at 5:38 PM Jun Rao <j...@confluent.io.invalid> > > > wrote: > > > >> > > > >>> Hi, Justine, > > > >>> > > > >>> Thanks for the reply. > > > >>> > > > >>> Since AddPartitions is an inter broker request, will its version be > > > gated > > > >>> only by TV or other features like MV too? For example, if we need > to > > > >>> change > > > >>> the protocol for AddPartitions for reasons other than txn > > verification > > > in > > > >>> the future, will the new version be gated by a new MV? If so, does > > > >>> downgrading a TV imply potential downgrade of MV too? > > > >>> > > > >>> Jun > > > >>> > > > >>> > > > >>> > > > >>> On Mon, Feb 5, 2024 at 5:07 PM Justine Olshan > > > >>> <jols...@confluent.io.invalid> > > > >>> wrote: > > > >>> > > > >>> > One TV gates the flexible feature version (no rpcs involved, only > > the > > > >>> > transactional records that should only be gated by TV) > > > >>> > Another TV gates the ability to turn on kip-890 part 2. This > would > > > >>> gate the > > > >>> > version of Produce and EndTxn (likely only used by transactions), > > and > > > >>> > specifies a flag in AddPartitionsToTxn though the version is > > already > > > >>> used > > > >>> > without TV. > > > >>> > > > > >>> > I think the only concern is the Produce request and we could > > consider > > > >>> work > > > >>> > arounds similar to the AddPartitionsToTxn call. > > > >>> > > > > >>> > Justine > > > >>> > > > > >>> > On Mon, Feb 5, 2024 at 4:56 PM Jun Rao <j...@confluent.io.invalid > > > > > >>> wrote: > > > >>> > > > > >>> > > Hi, Justine, > > > >>> > > > > > >>> > > Which PRC/record protocols will TV guard? Going forward, will > > those > > > >>> > > PRC/record protocols only be guarded by TV and not by other > > > features > > > >>> like > > > >>> > > MV? > > > >>> > > > > > >>> > > Thanks, > > > >>> > > > > > >>> > > Jun > > > >>> > > > > > >>> > > On Mon, Feb 5, 2024 at 2:41 PM Justine Olshan > > > >>> > <jols...@confluent.io.invalid > > > >>> > > > > > > >>> > > wrote: > > > >>> > > > > > >>> > > > Hi Jun, > > > >>> > > > > > > >>> > > > Sorry I think I misunderstood your question or answered > > > >>> incorrectly. > > > >>> > The > > > >>> > > TV > > > >>> > > > version should ideally be fully independent from MV. > > > >>> > > > At least for the changes I proposed, TV should not affect MV > > and > > > MV > > > >>> > > should > > > >>> > > > not affect TV/ > > > >>> > > > > > > >>> > > > I think if we downgrade TV, only that feature should > downgrade. > > > >>> > Likewise > > > >>> > > > the same with MV. The finalizedFeatures should just reflect > the > > > >>> feature > > > >>> > > > downgrade we made. > > > >>> > > > > > > >>> > > > I also plan to write a new KIP for managing the disk format > and > > > >>> upgrade > > > >>> > > > tool as we will need new flags to support these features. > That > > > >>> should > > > >>> > > help > > > >>> > > > clarify some things. > > > >>> > > > > > > >>> > > > Justine > > > >>> > > > > > > >>> > > > On Mon, Feb 5, 2024 at 11:03 AM Jun Rao > > <j...@confluent.io.invalid > > > > > > > >>> > > wrote: > > > >>> > > > > > > >>> > > > > Hi, Justine, > > > >>> > > > > > > > >>> > > > > Thanks for the reply. > > > >>> > > > > > > > >>> > > > > So, if we downgrade TV, we could implicitly downgrade > another > > > >>> feature > > > >>> > > > (say > > > >>> > > > > MV) that has dependency (e.g. RPC). What would we return > for > > > >>> > > > > FinalizedFeatures for MV in ApiVersionsResponse in that > case? > > > >>> > > > > > > > >>> > > > > Thanks, > > > >>> > > > > > > > >>> > > > > Jun > > > >>> > > > > > > > >>> > > > > On Fri, Feb 2, 2024 at 1:06 PM Justine Olshan > > > >>> > > > <jols...@confluent.io.invalid > > > >>> > > > > > > > > >>> > > > > wrote: > > > >>> > > > > > > > >>> > > > > > Hey Jun, > > > >>> > > > > > > > > >>> > > > > > Yes, the idea is that if we downgrade TV (transaction > > > version) > > > >>> we > > > >>> > > will > > > >>> > > > > stop > > > >>> > > > > > using the add partitions to txn optimization and stop > > writing > > > >>> the > > > >>> > > > > flexible > > > >>> > > > > > feature version of the log. > > > >>> > > > > > In the compatibility section I included some explanations > > on > > > >>> how > > > >>> > this > > > >>> > > > is > > > >>> > > > > > done. > > > >>> > > > > > > > > >>> > > > > > Thanks, > > > >>> > > > > > Justine > > > >>> > > > > > > > > >>> > > > > > On Fri, Feb 2, 2024 at 11:12 AM Jun Rao > > > >>> <j...@confluent.io.invalid> > > > >>> > > > > wrote: > > > >>> > > > > > > > > >>> > > > > > > Hi, Justine, > > > >>> > > > > > > > > > >>> > > > > > > Thanks for the update. > > > >>> > > > > > > > > > >>> > > > > > > If we ever downgrade the transaction feature, any > feature > > > >>> > depending > > > >>> > > > on > > > >>> > > > > > > changes on top of those RPC/record > > > >>> > > > > > > (AddPartitionsToTxnRequest/TransactionLogValue) changes > > > made > > > >>> in > > > >>> > > > KIP-890 > > > >>> > > > > > > will be automatically downgraded too? > > > >>> > > > > > > > > > >>> > > > > > > Jun > > > >>> > > > > > > > > > >>> > > > > > > On Tue, Jan 30, 2024 at 3:32 PM Justine Olshan > > > >>> > > > > > > <jols...@confluent.io.invalid> > > > >>> > > > > > > wrote: > > > >>> > > > > > > > > > >>> > > > > > > > Hey Jun, > > > >>> > > > > > > > > > > >>> > > > > > > > I wanted to get back to you about your questions > about > > > >>> MV/IBP. > > > >>> > > > > > > > > > > >>> > > > > > > > Looking at the options, I think it makes the most > sense > > > to > > > >>> > > create a > > > >>> > > > > > > > separate feature for transactions and use that to > > version > > > >>> gate > > > >>> > > the > > > >>> > > > > > > features > > > >>> > > > > > > > we need to version gate (flexible transactional state > > > >>> records > > > >>> > and > > > >>> > > > > using > > > >>> > > > > > > the > > > >>> > > > > > > > new protocol) > > > >>> > > > > > > > I've updated the KIP to include this change. > Hopefully > > > >>> that's > > > >>> > > > > > everything > > > >>> > > > > > > we > > > >>> > > > > > > > need for this KIP :) > > > >>> > > > > > > > > > > >>> > > > > > > > Justine > > > >>> > > > > > > > > > > >>> > > > > > > > > > > >>> > > > > > > > On Mon, Jan 22, 2024 at 3:17 PM Justine Olshan < > > > >>> > > > jols...@confluent.io > > > >>> > > > > > > > > >>> > > > > > > > wrote: > > > >>> > > > > > > > > > > >>> > > > > > > > > Thanks Jun, > > > >>> > > > > > > > > > > > >>> > > > > > > > > I will update the KIP with the prev field for > prepare > > > as > > > >>> > well. > > > >>> > > > > > > > > > > > >>> > > > > > > > > PREPARE > > > >>> > > > > > > > > producerId: x > > > >>> > > > > > > > > previous/lastProducerId (tagged field): x > > > >>> > > > > > > > > nextProducerId (tagged field): empty or z if y will > > > >>> overflow > > > >>> > > > > > > > > producerEpoch: y + 1 > > > >>> > > > > > > > > > > > >>> > > > > > > > > COMPLETE > > > >>> > > > > > > > > producerId: x or z if y overflowed > > > >>> > > > > > > > > previous/lastProducerId (tagged field): x > > > >>> > > > > > > > > nextProducerId (tagged field): empty > > > >>> > > > > > > > > producerEpoch: y + 1 or 0 if we overflowed > > > >>> > > > > > > > > > > > >>> > > > > > > > > Thanks again, > > > >>> > > > > > > > > Justine > > > >>> > > > > > > > > > > > >>> > > > > > > > > On Mon, Jan 22, 2024 at 3:15 PM Jun Rao > > > >>> > > <j...@confluent.io.invalid > > > >>> > > > > > > > >>> > > > > > > > wrote: > > > >>> > > > > > > > > > > > >>> > > > > > > > >> Hi, Justine, > > > >>> > > > > > > > >> > > > >>> > > > > > > > >> 101.3 Thanks for the explanation. > > > >>> > > > > > > > >> (1) My point was that the coordinator could fail > > right > > > >>> after > > > >>> > > > > writing > > > >>> > > > > > > the > > > >>> > > > > > > > >> prepare marker. When the new txn coordinator > > generates > > > >>> the > > > >>> > > > > complete > > > >>> > > > > > > > marker > > > >>> > > > > > > > >> after the failover, it needs some field from the > > > prepare > > > >>> > > marker > > > >>> > > > to > > > >>> > > > > > > > >> determine whether it's written by the new client. > > > >>> > > > > > > > >> > > > >>> > > > > > > > >> (2) The changing of the behavior sounds good to > me. > > We > > > >>> only > > > >>> > > want > > > >>> > > > > to > > > >>> > > > > > > > return > > > >>> > > > > > > > >> success if the prepare state is written by the new > > > >>> client. > > > >>> > So, > > > >>> > > > in > > > >>> > > > > > the > > > >>> > > > > > > > >> non-overflow case, it seems that we also need sth > in > > > the > > > >>> > > prepare > > > >>> > > > > > > marker > > > >>> > > > > > > > to > > > >>> > > > > > > > >> tell us whether it's written by the new client. > > > >>> > > > > > > > >> > > > >>> > > > > > > > >> 112. Thanks for the explanation. That sounds good > to > > > me. > > > >>> > > > > > > > >> > > > >>> > > > > > > > >> Jun > > > >>> > > > > > > > >> > > > >>> > > > > > > > >> On Mon, Jan 22, 2024 at 11:32 AM Justine Olshan > > > >>> > > > > > > > >> <jols...@confluent.io.invalid> wrote: > > > >>> > > > > > > > >> > > > >>> > > > > > > > >> > 101.3 I realized that I actually have two > > questions. > > > >>> > > > > > > > >> > > (1) In the non-overflow case, we need to write > > the > > > >>> > > previous > > > >>> > > > > > > produce > > > >>> > > > > > > > Id > > > >>> > > > > > > > >> > tagged field in the end maker so that we know if > > the > > > >>> > marker > > > >>> > > is > > > >>> > > > > > from > > > >>> > > > > > > > the > > > >>> > > > > > > > >> new > > > >>> > > > > > > > >> > client. Since the end maker is derived from the > > > >>> prepare > > > >>> > > > marker, > > > >>> > > > > > > should > > > >>> > > > > > > > >> we > > > >>> > > > > > > > >> > write the previous produce Id in the prepare > > marker > > > >>> field > > > >>> > > too? > > > >>> > > > > > > > >> Otherwise, > > > >>> > > > > > > > >> > we will lose this information when deriving the > > end > > > >>> > marker. > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > The "previous" producer ID is in the normal > > producer > > > >>> ID > > > >>> > > field. > > > >>> > > > > So > > > >>> > > > > > > yes, > > > >>> > > > > > > > >> we > > > >>> > > > > > > > >> > need it in prepare and that was always the plan. > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > Maybe it is a bit unclear so I will enumerate > the > > > >>> fields > > > >>> > and > > > >>> > > > add > > > >>> > > > > > > them > > > >>> > > > > > > > to > > > >>> > > > > > > > >> > the KIP if that helps. > > > >>> > > > > > > > >> > Say we have producer ID x and epoch y. When we > > > >>> overflow > > > >>> > > epoch > > > >>> > > > y > > > >>> > > > > we > > > >>> > > > > > > get > > > >>> > > > > > > > >> > producer ID Z. > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > PREPARE > > > >>> > > > > > > > >> > producerId: x > > > >>> > > > > > > > >> > previous/lastProducerId (tagged field): empty > > > >>> > > > > > > > >> > nextProducerId (tagged field): empty or z if y > > will > > > >>> > overflow > > > >>> > > > > > > > >> > producerEpoch: y + 1 > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > COMPLETE > > > >>> > > > > > > > >> > producerId: x or z if y overflowed > > > >>> > > > > > > > >> > previous/lastProducerId (tagged field): x > > > >>> > > > > > > > >> > nextProducerId (tagged field): empty > > > >>> > > > > > > > >> > producerEpoch: y + 1 or 0 if we overflowed > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > (2) In the prepare phase, if we retry and see > > epoch > > > - > > > >>> 1 + > > > >>> > ID > > > >>> > > > in > > > >>> > > > > > last > > > >>> > > > > > > > >> seen > > > >>> > > > > > > > >> > fields and are issuing the same command (ie > commit > > > not > > > >>> > > abort), > > > >>> > > > > we > > > >>> > > > > > > > return > > > >>> > > > > > > > >> > success. The logic before KIP-890 seems to > return > > > >>> > > > > > > > >> CONCURRENT_TRANSACTIONS > > > >>> > > > > > > > >> > in this case. Are we intentionally making this > > > change? > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > Hmm -- we would fence the producer if the epoch > is > > > >>> bumped > > > >>> > > and > > > >>> > > > we > > > >>> > > > > > > get a > > > >>> > > > > > > > >> > lower epoch. Yes -- we are intentionally adding > > this > > > >>> to > > > >>> > > > prevent > > > >>> > > > > > > > fencing. > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > 112. We already merged the code that adds the > > > >>> VerifyOnly > > > >>> > > field > > > >>> > > > > in > > > >>> > > > > > > > >> > AddPartitionsToTxnRequest, which is an inter > > broker > > > >>> > request. > > > >>> > > > It > > > >>> > > > > > > seems > > > >>> > > > > > > > >> that > > > >>> > > > > > > > >> > we didn't bump up the IBP for that. Do you know > > why? > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > We no longer need IBP for all interbroker > requests > > > as > > > >>> > > > > ApiVersions > > > >>> > > > > > > > should > > > >>> > > > > > > > >> > correctly gate versioning. > > > >>> > > > > > > > >> > We also handle unsupported version errors > > correctly > > > >>> if we > > > >>> > > > > receive > > > >>> > > > > > > them > > > >>> > > > > > > > >> in > > > >>> > > > > > > > >> > edge cases like upgrades/downgrades. > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > Justine > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > On Mon, Jan 22, 2024 at 11:00 AM Jun Rao > > > >>> > > > > <j...@confluent.io.invalid > > > >>> > > > > > > > > > >>> > > > > > > > >> wrote: > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > >>> > > > > > > > >> > > Thanks for the reply. > > > >>> > > > > > > > >> > > > > > >>> > > > > > > > >> > > 101.3 I realized that I actually have two > > > questions. > > > >>> > > > > > > > >> > > (1) In the non-overflow case, we need to write > > the > > > >>> > > previous > > > >>> > > > > > > produce > > > >>> > > > > > > > Id > > > >>> > > > > > > > >> > > tagged field in the end maker so that we know > if > > > the > > > >>> > > marker > > > >>> > > > is > > > >>> > > > > > > from > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > new > > > >>> > > > > > > > >> > > client. Since the end maker is derived from > the > > > >>> prepare > > > >>> > > > > marker, > > > >>> > > > > > > > >> should we > > > >>> > > > > > > > >> > > write the previous produce Id in the prepare > > > marker > > > >>> > field > > > >>> > > > too? > > > >>> > > > > > > > >> Otherwise, > > > >>> > > > > > > > >> > > we will lose this information when deriving > the > > > end > > > >>> > > marker. > > > >>> > > > > > > > >> > > (2) In the prepare phase, if we retry and see > > > epoch > > > >>> - 1 > > > >>> > + > > > >>> > > ID > > > >>> > > > > in > > > >>> > > > > > > last > > > >>> > > > > > > > >> seen > > > >>> > > > > > > > >> > > fields and are issuing the same command (ie > > commit > > > >>> not > > > >>> > > > abort), > > > >>> > > > > > we > > > >>> > > > > > > > >> return > > > >>> > > > > > > > >> > > success. The logic before KIP-890 seems to > > return > > > >>> > > > > > > > >> CONCURRENT_TRANSACTIONS > > > >>> > > > > > > > >> > > in this case. Are we intentionally making this > > > >>> change? > > > >>> > > > > > > > >> > > > > > >>> > > > > > > > >> > > 112. We already merged the code that adds the > > > >>> VerifyOnly > > > >>> > > > field > > > >>> > > > > > in > > > >>> > > > > > > > >> > > AddPartitionsToTxnRequest, which is an inter > > > broker > > > >>> > > request. > > > >>> > > > > It > > > >>> > > > > > > > seems > > > >>> > > > > > > > >> > that > > > >>> > > > > > > > >> > > we didn't bump up the IBP for that. Do you > know > > > why? > > > >>> > > > > > > > >> > > > > > >>> > > > > > > > >> > > Jun > > > >>> > > > > > > > >> > > > > > >>> > > > > > > > >> > > On Fri, Jan 19, 2024 at 4:50 PM Justine Olshan > > > >>> > > > > > > > >> > > <jols...@confluent.io.invalid> > > > >>> > > > > > > > >> > > wrote: > > > >>> > > > > > > > >> > > > > > >>> > > > > > > > >> > > > Hi Jun, > > > >>> > > > > > > > >> > > > > > > >>> > > > > > > > >> > > > 101.3 I can change "last seen" to "current > > > >>> producer id > > > >>> > > and > > > >>> > > > > > > epoch" > > > >>> > > > > > > > if > > > >>> > > > > > > > >> > that > > > >>> > > > > > > > >> > > > was the part that was confusing > > > >>> > > > > > > > >> > > > 110 I can mention this > > > >>> > > > > > > > >> > > > 111 I can do that > > > >>> > > > > > > > >> > > > 112 We still need it. But I am still > > finalizing > > > >>> the > > > >>> > > > design. > > > >>> > > > > I > > > >>> > > > > > > will > > > >>> > > > > > > > >> > update > > > >>> > > > > > > > >> > > > the KIP once I get the information > finalized. > > > >>> Sorry > > > >>> > for > > > >>> > > > the > > > >>> > > > > > > > delays. > > > >>> > > > > > > > >> > > > > > > >>> > > > > > > > >> > > > Justine > > > >>> > > > > > > > >> > > > > > > >>> > > > > > > > >> > > > On Fri, Jan 19, 2024 at 10:50 AM Jun Rao > > > >>> > > > > > > <j...@confluent.io.invalid > > > >>> > > > > > > > > > > > >>> > > > > > > > >> > > wrote: > > > >>> > > > > > > > >> > > > > > > >>> > > > > > > > >> > > > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > Thanks for the reply. > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > 101.3 In the non-overflow case, the > previous > > > ID > > > >>> is > > > >>> > the > > > >>> > > > > same > > > >>> > > > > > as > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > > > produce > > > >>> > > > > > > > >> > > > > ID for the complete marker too, but we set > > the > > > >>> > > previous > > > >>> > > > ID > > > >>> > > > > > in > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > > > complete > > > >>> > > > > > > > >> > > > > marker. Earlier you mentioned that this is > > to > > > >>> know > > > >>> > > that > > > >>> > > > > the > > > >>> > > > > > > > >> marker is > > > >>> > > > > > > > >> > > > > written by the new client so that we could > > > >>> return > > > >>> > > > success > > > >>> > > > > on > > > >>> > > > > > > > >> retried > > > >>> > > > > > > > >> > > > > endMarker requests. I was trying to > > understand > > > >>> why > > > >>> > > this > > > >>> > > > is > > > >>> > > > > > not > > > >>> > > > > > > > >> needed > > > >>> > > > > > > > >> > > for > > > >>> > > > > > > > >> > > > > the prepare marker since retry can happen > in > > > the > > > >>> > > prepare > > > >>> > > > > > state > > > >>> > > > > > > > >> too. > > > >>> > > > > > > > >> > Is > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > reason that in the prepare state, we > return > > > >>> > > > > > > > >> CONCURRENT_TRANSACTIONS > > > >>> > > > > > > > >> > > > instead > > > >>> > > > > > > > >> > > > > of success on retried endMaker requests? > If > > > so, > > > >>> > should > > > >>> > > > we > > > >>> > > > > > > change > > > >>> > > > > > > > >> "If > > > >>> > > > > > > > >> > we > > > >>> > > > > > > > >> > > > > retry and see epoch - 1 + ID in last seen > > > >>> fields and > > > >>> > > are > > > >>> > > > > > > issuing > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > same > > > >>> > > > > > > > >> > > > > command (ie commit not abort) we can > return > > > >>> (with > > > >>> > the > > > >>> > > > new > > > >>> > > > > > > > epoch)" > > > >>> > > > > > > > >> > > > > accordingly? > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > 110. Yes, without this KIP, a delayed > > endMaker > > > >>> > request > > > >>> > > > > > carries > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > same > > > >>> > > > > > > > >> > > > > epoch and won't be fenced. This can > > > >>> commit/abort a > > > >>> > > > future > > > >>> > > > > > > > >> transaction > > > >>> > > > > > > > >> > > > > unexpectedly. I am not sure if we have > seen > > > >>> this in > > > >>> > > > > practice > > > >>> > > > > > > > >> though. > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > 111. Sounds good. It would be useful to > make > > > it > > > >>> > clear > > > >>> > > > that > > > >>> > > > > > we > > > >>> > > > > > > > can > > > >>> > > > > > > > >> now > > > >>> > > > > > > > >> > > > > populate the lastSeen field from the log > > > >>> reliably. > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > 112. Yes, I was referring to > > > >>> > AddPartitionsToTxnRequest > > > >>> > > > > since > > > >>> > > > > > > > it's > > > >>> > > > > > > > >> > > called > > > >>> > > > > > > > >> > > > > across brokers and we are changing its > > schema. > > > >>> Are > > > >>> > you > > > >>> > > > > > saying > > > >>> > > > > > > we > > > >>> > > > > > > > >> > don't > > > >>> > > > > > > > >> > > > need > > > >>> > > > > > > > >> > > > > it any more? I thought that we already > > > >>> implemented > > > >>> > the > > > >>> > > > > > server > > > >>> > > > > > > > side > > > >>> > > > > > > > >> > > > > verification logic based on > > > >>> > AddPartitionsToTxnRequest > > > >>> > > > > across > > > >>> > > > > > > > >> brokers. > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > Jun > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > On Thu, Jan 18, 2024 at 5:05 PM Justine > > Olshan > > > >>> > > > > > > > >> > > > > <jols...@confluent.io.invalid> > > > >>> > > > > > > > >> > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > > Hey Jun, > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > 101.3 We don't set the previous ID in > the > > > >>> Prepare > > > >>> > > > field > > > >>> > > > > > > since > > > >>> > > > > > > > we > > > >>> > > > > > > > >> > > don't > > > >>> > > > > > > > >> > > > > need > > > >>> > > > > > > > >> > > > > > it. It is the same producer ID as the > main > > > >>> > producer > > > >>> > > ID > > > >>> > > > > > > field. > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > 110 Hmm -- maybe I need to reread your > > > message > > > >>> > about > > > >>> > > > > > delayed > > > >>> > > > > > > > >> > markers. > > > >>> > > > > > > > >> > > > If > > > >>> > > > > > > > >> > > > > we > > > >>> > > > > > > > >> > > > > > receive a delayed endTxn marker after > the > > > >>> > > transaction > > > >>> > > > is > > > >>> > > > > > > > already > > > >>> > > > > > > > >> > > > > complete? > > > >>> > > > > > > > >> > > > > > So we will commit the next transaction > > early > > > >>> > without > > > >>> > > > the > > > >>> > > > > > > fixes > > > >>> > > > > > > > >> in > > > >>> > > > > > > > >> > > part > > > >>> > > > > > > > >> > > > 2? > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > 111 Yes -- this terminology was used in > a > > > >>> previous > > > >>> > > KIP > > > >>> > > > > and > > > >>> > > > > > > > never > > > >>> > > > > > > > >> > > > > > implemented it in the log -- only in > > memory > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > 112 Hmm -- which interbroker protocol > are > > > you > > > >>> > > > referring > > > >>> > > > > > to? > > > >>> > > > > > > I > > > >>> > > > > > > > am > > > >>> > > > > > > > >> > > > working > > > >>> > > > > > > > >> > > > > on > > > >>> > > > > > > > >> > > > > > the design for the work to remove the > > extra > > > >>> add > > > >>> > > > > partitions > > > >>> > > > > > > > call > > > >>> > > > > > > > >> > and I > > > >>> > > > > > > > >> > > > > right > > > >>> > > > > > > > >> > > > > > now the design bumps MV. I have yet to > > > update > > > >>> that > > > >>> > > > > section > > > >>> > > > > > > as > > > >>> > > > > > > > I > > > >>> > > > > > > > >> > > > finalize > > > >>> > > > > > > > >> > > > > > the design so please stay tuned. Was > there > > > >>> > anything > > > >>> > > > else > > > >>> > > > > > you > > > >>> > > > > > > > >> > thought > > > >>> > > > > > > > >> > > > > needed > > > >>> > > > > > > > >> > > > > > MV bump? > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > Justine > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > On Thu, Jan 18, 2024 at 3:07 PM Jun Rao > > > >>> > > > > > > > >> <j...@confluent.io.invalid> > > > >>> > > > > > > > >> > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > I don't see this create any issue. It > > just > > > >>> makes > > > >>> > > it > > > >>> > > > a > > > >>> > > > > > bit > > > >>> > > > > > > > >> hard to > > > >>> > > > > > > > >> > > > > explain > > > >>> > > > > > > > >> > > > > > > what this non-tagged produce id field > > > >>> means. We > > > >>> > > are > > > >>> > > > > > > > >> essentially > > > >>> > > > > > > > >> > > > trying > > > >>> > > > > > > > >> > > > > to > > > >>> > > > > > > > >> > > > > > > combine two actions (completing a txn > > and > > > >>> init a > > > >>> > > new > > > >>> > > > > > > produce > > > >>> > > > > > > > >> Id) > > > >>> > > > > > > > >> > > in a > > > >>> > > > > > > > >> > > > > > > single record. But, this may be fine > > too. > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > A few other follow up comments. > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > 101.3 I guess the reason that we only > > set > > > >>> the > > > >>> > > > previous > > > >>> > > > > > > > >> produce id > > > >>> > > > > > > > >> > > > > tagged > > > >>> > > > > > > > >> > > > > > > field in the complete marker, but not > in > > > the > > > >>> > > prepare > > > >>> > > > > > > marker, > > > >>> > > > > > > > >> is > > > >>> > > > > > > > >> > > that > > > >>> > > > > > > > >> > > > in > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > prepare state, we always return > > > >>> > > > > CONCURRENT_TRANSACTIONS > > > >>> > > > > > on > > > >>> > > > > > > > >> > retried > > > >>> > > > > > > > >> > > > > > endMaker > > > >>> > > > > > > > >> > > > > > > requests? > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > 110. "I believe your second point is > > > >>> mentioned > > > >>> > in > > > >>> > > > the > > > >>> > > > > > > KIP. I > > > >>> > > > > > > > >> can > > > >>> > > > > > > > >> > > add > > > >>> > > > > > > > >> > > > > more > > > >>> > > > > > > > >> > > > > > > text on > > > >>> > > > > > > > >> > > > > > > this if it is helpful. > > > >>> > > > > > > > >> > > > > > > > The delayed message case can also > > > violate > > > >>> EOS > > > >>> > if > > > >>> > > > the > > > >>> > > > > > > > delayed > > > >>> > > > > > > > >> > > > message > > > >>> > > > > > > > >> > > > > > > comes in after the next > > addPartitionsToTxn > > > >>> > request > > > >>> > > > > comes > > > >>> > > > > > > in. > > > >>> > > > > > > > >> > > > > Effectively > > > >>> > > > > > > > >> > > > > > we > > > >>> > > > > > > > >> > > > > > > may see a message from a previous > > > (aborted) > > > >>> > > > > transaction > > > >>> > > > > > > > become > > > >>> > > > > > > > >> > part > > > >>> > > > > > > > >> > > > of > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > next transaction." > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > The above is the case when a delayed > > > >>> message is > > > >>> > > > > appended > > > >>> > > > > > > to > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > data > > > >>> > > > > > > > >> > > > > > > partition. What I mentioned is a > > slightly > > > >>> > > different > > > >>> > > > > case > > > >>> > > > > > > > when > > > >>> > > > > > > > >> a > > > >>> > > > > > > > >> > > > delayed > > > >>> > > > > > > > >> > > > > > > marker is appended to the transaction > > log > > > >>> > > partition. > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > 111. The KIP says "Once we move past > the > > > >>> Prepare > > > >>> > > and > > > >>> > > > > > > > Complete > > > >>> > > > > > > > >> > > states, > > > >>> > > > > > > > >> > > > > we > > > >>> > > > > > > > >> > > > > > > don’t need to worry about lastSeen > > fields > > > >>> and > > > >>> > > clear > > > >>> > > > > > them, > > > >>> > > > > > > > just > > > >>> > > > > > > > >> > > handle > > > >>> > > > > > > > >> > > > > > state > > > >>> > > > > > > > >> > > > > > > transitions as normal.". Is the > lastSeen > > > >>> field > > > >>> > the > > > >>> > > > > same > > > >>> > > > > > as > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > > > previous > > > >>> > > > > > > > >> > > > > > > Produce Id tagged field in > > > >>> TransactionLogValue? > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > 112. Since the kip changes the > > > inter-broker > > > >>> > > > protocol, > > > >>> > > > > > > should > > > >>> > > > > > > > >> we > > > >>> > > > > > > > >> > > bump > > > >>> > > > > > > > >> > > > up > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > MV/IBP version? Is this feature only > for > > > the > > > >>> > KRaft > > > >>> > > > > mode? > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > Thanks, > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > Jun > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > On Wed, Jan 17, 2024 at 11:13 AM > Justine > > > >>> Olshan > > > >>> > > > > > > > >> > > > > > > <jols...@confluent.io.invalid> wrote: > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > > Hey Jun, > > > >>> > > > > > > > >> > > > > > > > > > > >>> > > > > > > > >> > > > > > > > I'm glad we are getting to > convergence > > > on > > > >>> the > > > >>> > > > > design. > > > >>> > > > > > :) > > > >>> > > > > > > > >> > > > > > > > > > > >>> > > > > > > > >> > > > > > > > While I understand it seems a little > > > >>> "weird". > > > >>> > > I'm > > > >>> > > > > not > > > >>> > > > > > > sure > > > >>> > > > > > > > >> what > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > > benefit > > > >>> > > > > > > > >> > > > > > > > of writing an extra record to the > log. > > > >>> > > > > > > > >> > > > > > > > Is the concern a tool to describe > > > >>> transactions > > > >>> > > > won't > > > >>> > > > > > > work > > > >>> > > > > > > > >> (ie, > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > > complete > > > >>> > > > > > > > >> > > > > > > > state is needed to calculate the > time > > > >>> since > > > >>> > the > > > >>> > > > > > > > transaction > > > >>> > > > > > > > >> > > > > completed?) > > > >>> > > > > > > > >> > > > > > > > If we have a reason like this, it is > > > >>> enough to > > > >>> > > > > > convince > > > >>> > > > > > > me > > > >>> > > > > > > > >> we > > > >>> > > > > > > > >> > > need > > > >>> > > > > > > > >> > > > > such > > > >>> > > > > > > > >> > > > > > > an > > > >>> > > > > > > > >> > > > > > > > extra record. It seems like it would > > be > > > >>> > > replacing > > > >>> > > > > the > > > >>> > > > > > > > record > > > >>> > > > > > > > >> > > > written > > > >>> > > > > > > > >> > > > > on > > > >>> > > > > > > > >> > > > > > > > InitProducerId. Is this correct? > > > >>> > > > > > > > >> > > > > > > > > > > >>> > > > > > > > >> > > > > > > > Thanks, > > > >>> > > > > > > > >> > > > > > > > Justine > > > >>> > > > > > > > >> > > > > > > > > > > >>> > > > > > > > >> > > > > > > > On Tue, Jan 16, 2024 at 5:14 PM Jun > > Rao > > > >>> > > > > > > > >> > <j...@confluent.io.invalid > > > >>> > > > > > > > >> > > > > > > >>> > > > > > > > >> > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > Thanks for the explanation. I > > > >>> understand the > > > >>> > > > > > intention > > > >>> > > > > > > > >> now. > > > >>> > > > > > > > >> > In > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > overflow > > > >>> > > > > > > > >> > > > > > > > > case, we set the non-tagged field > to > > > >>> the old > > > >>> > > pid > > > >>> > > > > > (and > > > >>> > > > > > > > the > > > >>> > > > > > > > >> max > > > >>> > > > > > > > >> > > > > epoch) > > > >>> > > > > > > > >> > > > > > in > > > >>> > > > > > > > >> > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > prepare marker so that we could > > > >>> correctly > > > >>> > > write > > > >>> > > > > the > > > >>> > > > > > > > >> marker to > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > data > > > >>> > > > > > > > >> > > > > > > > > partition if the broker > downgrades. > > > When > > > >>> > > writing > > > >>> > > > > the > > > >>> > > > > > > > >> complete > > > >>> > > > > > > > >> > > > > marker, > > > >>> > > > > > > > >> > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > know the marker has already been > > > >>> written to > > > >>> > > the > > > >>> > > > > data > > > >>> > > > > > > > >> > partition. > > > >>> > > > > > > > >> > > > We > > > >>> > > > > > > > >> > > > > > set > > > >>> > > > > > > > >> > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > non-tagged field to the new pid to > > > avoid > > > >>> > > > > > > > >> > > > InvalidPidMappingException > > > >>> > > > > > > > >> > > > > > in > > > >>> > > > > > > > >> > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > client if the broker downgrades. > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > The above seems to work. It's > just a > > > bit > > > >>> > > > > > inconsistent > > > >>> > > > > > > > for > > > >>> > > > > > > > >> a > > > >>> > > > > > > > >> > > > prepare > > > >>> > > > > > > > >> > > > > > > > marker > > > >>> > > > > > > > >> > > > > > > > > and a complete marker to use > > different > > > >>> pids > > > >>> > in > > > >>> > > > > this > > > >>> > > > > > > > >> special > > > >>> > > > > > > > >> > > case. > > > >>> > > > > > > > >> > > > > If > > > >>> > > > > > > > >> > > > > > we > > > >>> > > > > > > > >> > > > > > > > > downgrade with the complete > marker, > > it > > > >>> seems > > > >>> > > > that > > > >>> > > > > we > > > >>> > > > > > > > will > > > >>> > > > > > > > >> > never > > > >>> > > > > > > > >> > > > be > > > >>> > > > > > > > >> > > > > > able > > > >>> > > > > > > > >> > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > write the complete marker with the > > old > > > >>> pid. > > > >>> > > Not > > > >>> > > > > sure > > > >>> > > > > > > if > > > >>> > > > > > > > it > > > >>> > > > > > > > >> > > causes > > > >>> > > > > > > > >> > > > > any > > > >>> > > > > > > > >> > > > > > > > > issue, but it seems a bit weird. > > > >>> Instead of > > > >>> > > > > writing > > > >>> > > > > > > the > > > >>> > > > > > > > >> > > complete > > > >>> > > > > > > > >> > > > > > marker > > > >>> > > > > > > > >> > > > > > > > > with the new pid, could we write > two > > > >>> > records: > > > >>> > > a > > > >>> > > > > > > complete > > > >>> > > > > > > > >> > marker > > > >>> > > > > > > > >> > > > > with > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > old pid followed by a > > > >>> TransactionLogValue > > > >>> > with > > > >>> > > > the > > > >>> > > > > > new > > > >>> > > > > > > > pid > > > >>> > > > > > > > >> > and > > > >>> > > > > > > > >> > > an > > > >>> > > > > > > > >> > > > > > empty > > > >>> > > > > > > > >> > > > > > > > > state? We could make the two > records > > > in > > > >>> the > > > >>> > > same > > > >>> > > > > > batch > > > >>> > > > > > > > so > > > >>> > > > > > > > >> > that > > > >>> > > > > > > > >> > > > they > > > >>> > > > > > > > >> > > > > > > will > > > >>> > > > > > > > >> > > > > > > > be > > > >>> > > > > > > > >> > > > > > > > > added to the log atomically. > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > Thanks, > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > Jun > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > On Fri, Jan 12, 2024 at 5:40 PM > > > Justine > > > >>> > Olshan > > > >>> > > > > > > > >> > > > > > > > > <jols...@confluent.io.invalid> > > > >>> > > > > > > > >> > > > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > (1) the prepare marker is > written, > > > >>> but the > > > >>> > > > > endTxn > > > >>> > > > > > > > >> response > > > >>> > > > > > > > >> > is > > > >>> > > > > > > > >> > > > not > > > >>> > > > > > > > >> > > > > > > > > received > > > >>> > > > > > > > >> > > > > > > > > > by the client when the server > > > >>> downgrades > > > >>> > > > > > > > >> > > > > > > > > > (2) the prepare marker is > > written, > > > >>> the > > > >>> > > endTxn > > > >>> > > > > > > > response > > > >>> > > > > > > > >> is > > > >>> > > > > > > > >> > > > > received > > > >>> > > > > > > > >> > > > > > > by > > > >>> > > > > > > > >> > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > client when the server > downgrades. > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > I think I am still a little > > > confused. > > > >>> In > > > >>> > > both > > > >>> > > > of > > > >>> > > > > > > these > > > >>> > > > > > > > >> > cases, > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > > > transaction log has the old > > producer > > > >>> ID. > > > >>> > We > > > >>> > > > > don't > > > >>> > > > > > > > write > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > new > > > >>> > > > > > > > >> > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > in the prepare marker's non > tagged > > > >>> fields. > > > >>> > > > > > > > >> > > > > > > > > > If the server downgrades now, it > > > would > > > >>> > read > > > >>> > > > the > > > >>> > > > > > > > records > > > >>> > > > > > > > >> not > > > >>> > > > > > > > >> > > in > > > >>> > > > > > > > >> > > > > > tagged > > > >>> > > > > > > > >> > > > > > > > > > fields and the complete marker > > will > > > >>> also > > > >>> > > have > > > >>> > > > > the > > > >>> > > > > > > old > > > >>> > > > > > > > >> > > producer > > > >>> > > > > > > > >> > > > > ID. > > > >>> > > > > > > > >> > > > > > > > > > (If we had used the new producer > > ID, > > > >>> we > > > >>> > > would > > > >>> > > > > not > > > >>> > > > > > > have > > > >>> > > > > > > > >> > > > > > transactional > > > >>> > > > > > > > >> > > > > > > > > > correctness since the producer > id > > > >>> doesn't > > > >>> > > > match > > > >>> > > > > > the > > > >>> > > > > > > > >> > > transaction > > > >>> > > > > > > > >> > > > > and > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > state would not be correct on > the > > > data > > > >>> > > > > partition.) > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > In the overflow case, I'd expect > > the > > > >>> > > following > > > >>> > > > > to > > > >>> > > > > > > > >> happen on > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > > client > > > >>> > > > > > > > >> > > > > > > > > side > > > >>> > > > > > > > >> > > > > > > > > > Case 1 -- we retry EndTxn -- it > > is > > > >>> the > > > >>> > same > > > >>> > > > > > > producer > > > >>> > > > > > > > ID > > > >>> > > > > > > > >> > and > > > >>> > > > > > > > >> > > > > epoch > > > >>> > > > > > > > >> > > > > > - > > > >>> > > > > > > > >> > > > > > > 1 > > > >>> > > > > > > > >> > > > > > > > > this > > > >>> > > > > > > > >> > > > > > > > > > would fence the producer > > > >>> > > > > > > > >> > > > > > > > > > Case 2 -- we don't retry EndTxn > > and > > > >>> use > > > >>> > the > > > >>> > > > new > > > >>> > > > > > > > >> producer id > > > >>> > > > > > > > >> > > > which > > > >>> > > > > > > > >> > > > > > > would > > > >>> > > > > > > > >> > > > > > > > > > result in > > InvalidPidMappingException > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > Maybe we can have special > handling > > > for > > > >>> > when > > > >>> > > a > > > >>> > > > > > server > > > >>> > > > > > > > >> > > > downgrades. > > > >>> > > > > > > > >> > > > > > When > > > >>> > > > > > > > >> > > > > > > > it > > > >>> > > > > > > > >> > > > > > > > > > reconnects we could get an API > > > version > > > >>> > > request > > > >>> > > > > > > showing > > > >>> > > > > > > > >> > > KIP-890 > > > >>> > > > > > > > >> > > > > > part 2 > > > >>> > > > > > > > >> > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > not supported. In that case, we > > can > > > >>> call > > > >>> > > > > > > > initProducerId > > > >>> > > > > > > > >> to > > > >>> > > > > > > > >> > > > abort > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > transaction. (In the overflow > > case, > > > >>> this > > > >>> > > > > correctly > > > >>> > > > > > > > gives > > > >>> > > > > > > > >> > us a > > > >>> > > > > > > > >> > > > new > > > >>> > > > > > > > >> > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > ID) > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > I guess the corresponding case > > would > > > >>> be > > > >>> > > where > > > >>> > > > > the > > > >>> > > > > > > > >> *complete > > > >>> > > > > > > > >> > > > > marker > > > >>> > > > > > > > >> > > > > > > *is > > > >>> > > > > > > > >> > > > > > > > > > written but the endTxn is not > > > >>> received by > > > >>> > > the > > > >>> > > > > > client > > > >>> > > > > > > > and > > > >>> > > > > > > > >> > the > > > >>> > > > > > > > >> > > > > server > > > >>> > > > > > > > >> > > > > > > > > > downgrades? This would result in > > the > > > >>> > > > transaction > > > >>> > > > > > > > >> > coordinator > > > >>> > > > > > > > >> > > > > having > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > new > > > >>> > > > > > > > >> > > > > > > > > > ID and not the old one. If the > > > client > > > >>> > > > retries, > > > >>> > > > > it > > > >>> > > > > > > > will > > > >>> > > > > > > > >> > > receive > > > >>> > > > > > > > >> > > > > an > > > >>> > > > > > > > >> > > > > > > > > > InvalidPidMappingException. The > > > >>> > > InitProducerId > > > >>> > > > > > > > scenario > > > >>> > > > > > > > >> > above > > > >>> > > > > > > > >> > > > > would > > > >>> > > > > > > > >> > > > > > > > help > > > >>> > > > > > > > >> > > > > > > > > > here too. > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > To be clear, my compatibility > > story > > > is > > > >>> > meant > > > >>> > > > to > > > >>> > > > > > > > support > > > >>> > > > > > > > >> > > > > downgrades > > > >>> > > > > > > > >> > > > > > > > server > > > >>> > > > > > > > >> > > > > > > > > > side in keeping the > transactional > > > >>> > > correctness. > > > >>> > > > > > > Keeping > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > > client > > > >>> > > > > > > > >> > > > > > > from > > > >>> > > > > > > > >> > > > > > > > > > fencing itself is not the > > priority. > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > Hope this helps. I can also add > > text > > > >>> in > > > >>> > the > > > >>> > > > KIP > > > >>> > > > > > > about > > > >>> > > > > > > > >> > > > > > InitProducerId > > > >>> > > > > > > > >> > > > > > > if > > > >>> > > > > > > > >> > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > think that fixes some edge > cases. > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > Justine > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > On Fri, Jan 12, 2024 at 4:10 PM > > Jun > > > >>> Rao > > > >>> > > > > > > > >> > > > <j...@confluent.io.invalid > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > Thanks for the reply. > > > >>> > > > > > > > >> > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > I agree that we don't need to > > > >>> optimize > > > >>> > for > > > >>> > > > > > fencing > > > >>> > > > > > > > >> during > > > >>> > > > > > > > >> > > > > > > downgrades. > > > >>> > > > > > > > >> > > > > > > > > > > Regarding consistency, there > are > > > two > > > >>> > > > possible > > > >>> > > > > > > cases: > > > >>> > > > > > > > >> (1) > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > > prepare > > > >>> > > > > > > > >> > > > > > > > > > marker > > > >>> > > > > > > > >> > > > > > > > > > > is written, but the endTxn > > > response > > > >>> is > > > >>> > not > > > >>> > > > > > > received > > > >>> > > > > > > > by > > > >>> > > > > > > > >> > the > > > >>> > > > > > > > >> > > > > client > > > >>> > > > > > > > >> > > > > > > > when > > > >>> > > > > > > > >> > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > server downgrades; (2) the > > > prepare > > > >>> > marker > > > >>> > > > is > > > >>> > > > > > > > written, > > > >>> > > > > > > > >> > the > > > >>> > > > > > > > >> > > > > endTxn > > > >>> > > > > > > > >> > > > > > > > > > response > > > >>> > > > > > > > >> > > > > > > > > > > is received by the client when > > the > > > >>> > server > > > >>> > > > > > > > downgrades. > > > >>> > > > > > > > >> In > > > >>> > > > > > > > >> > > (1), > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > > client > > > >>> > > > > > > > >> > > > > > > > > > > will have the old produce Id > and > > > in > > > >>> (2), > > > >>> > > the > > > >>> > > > > > > client > > > >>> > > > > > > > >> will > > > >>> > > > > > > > >> > > have > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > new > > > >>> > > > > > > > >> > > > > > > > > > > produce Id. If we downgrade > > right > > > >>> after > > > >>> > > the > > > >>> > > > > > > prepare > > > >>> > > > > > > > >> > marker, > > > >>> > > > > > > > >> > > > we > > > >>> > > > > > > > >> > > > > > > can't > > > >>> > > > > > > > >> > > > > > > > be > > > >>> > > > > > > > >> > > > > > > > > > > consistent to both (1) and (2) > > > >>> since we > > > >>> > > can > > > >>> > > > > only > > > >>> > > > > > > put > > > >>> > > > > > > > >> one > > > >>> > > > > > > > >> > > > value > > > >>> > > > > > > > >> > > > > in > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > existing produce Id field. > It's > > > >>> also not > > > >>> > > > clear > > > >>> > > > > > > which > > > >>> > > > > > > > >> case > > > >>> > > > > > > > >> > > is > > > >>> > > > > > > > >> > > > > more > > > >>> > > > > > > > >> > > > > > > > > likely. > > > >>> > > > > > > > >> > > > > > > > > > > So we could probably be > > consistent > > > >>> with > > > >>> > > > either > > > >>> > > > > > > case. > > > >>> > > > > > > > >> By > > > >>> > > > > > > > >> > > > putting > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > new > > > >>> > > > > > > > >> > > > > > > > > > > producer Id in the prepare > > marker, > > > >>> we > > > >>> > are > > > >>> > > > > > > consistent > > > >>> > > > > > > > >> with > > > >>> > > > > > > > >> > > > case > > > >>> > > > > > > > >> > > > > > (2) > > > >>> > > > > > > > >> > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > it > > > >>> > > > > > > > >> > > > > > > > > > > also has the slight benefit > that > > > the > > > >>> > > produce > > > >>> > > > > > field > > > >>> > > > > > > > in > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > > > prepare > > > >>> > > > > > > > >> > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > complete marker are consistent > > in > > > >>> the > > > >>> > > > overflow > > > >>> > > > > > > case. > > > >>> > > > > > > > >> > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > Jun > > > >>> > > > > > > > >> > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > On Fri, Jan 12, 2024 at > 3:11 PM > > > >>> Justine > > > >>> > > > Olshan > > > >>> > > > > > > > >> > > > > > > > > > > <jols...@confluent.io.invalid > > > > > >>> > > > > > > > >> > > > > > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > Hi Jun, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > In the case you describe, we > > > would > > > >>> > need > > > >>> > > to > > > >>> > > > > > have > > > >>> > > > > > > a > > > >>> > > > > > > > >> > delayed > > > >>> > > > > > > > >> > > > > > > request, > > > >>> > > > > > > > >> > > > > > > > > > send a > > > >>> > > > > > > > >> > > > > > > > > > > > successful EndTxn, and a > > > >>> successful > > > >>> > > > > > > > >> AddPartitionsToTxn > > > >>> > > > > > > > >> > > and > > > >>> > > > > > > > >> > > > > then > > > >>> > > > > > > > >> > > > > > > > have > > > >>> > > > > > > > >> > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > delayed EndTxn request go > > > through > > > >>> for > > > >>> > a > > > >>> > > > > given > > > >>> > > > > > > > >> producer. > > > >>> > > > > > > > >> > > > > > > > > > > > I'm trying to figure out if > it > > > is > > > >>> > > possible > > > >>> > > > > for > > > >>> > > > > > > the > > > >>> > > > > > > > >> > client > > > >>> > > > > > > > >> > > > to > > > >>> > > > > > > > >> > > > > > > > > transition > > > >>> > > > > > > > >> > > > > > > > > > > if > > > >>> > > > > > > > >> > > > > > > > > > > > a previous request is > delayed > > > >>> > somewhere. > > > >>> > > > But > > > >>> > > > > > > yes, > > > >>> > > > > > > > in > > > >>> > > > > > > > >> > this > > > >>> > > > > > > > >> > > > > case > > > >>> > > > > > > > >> > > > > > I > > > >>> > > > > > > > >> > > > > > > > > think > > > >>> > > > > > > > >> > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > would fence the client. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > Not for the overflow case. > In > > > the > > > >>> > > overflow > > > >>> > > > > > case, > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > > > producer > > > >>> > > > > > > > >> > > > > > ID > > > >>> > > > > > > > >> > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > epoch are different on the > > > marker > > > >>> and > > > >>> > on > > > >>> > > > the > > > >>> > > > > > new > > > >>> > > > > > > > >> > > > transaction. > > > >>> > > > > > > > >> > > > > > So > > > >>> > > > > > > > >> > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > want > > > >>> > > > > > > > >> > > > > > > > > > > > the marker to use the max > > epoch > > > >>> but > > > >>> > the > > > >>> > > > new > > > >>> > > > > > > > >> > transaction > > > >>> > > > > > > > >> > > > > should > > > >>> > > > > > > > >> > > > > > > > start > > > >>> > > > > > > > >> > > > > > > > > > > with > > > >>> > > > > > > > >> > > > > > > > > > > > the new ID and epoch 0 in > the > > > >>> > > > transactional > > > >>> > > > > > > state. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > In the server downgrade > case, > > we > > > >>> want > > > >>> > to > > > >>> > > > see > > > >>> > > > > > the > > > >>> > > > > > > > >> > producer > > > >>> > > > > > > > >> > > > ID > > > >>> > > > > > > > >> > > > > as > > > >>> > > > > > > > >> > > > > > > > that > > > >>> > > > > > > > >> > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > what the client will have. > If > > we > > > >>> > > complete > > > >>> > > > > the > > > >>> > > > > > > > >> commit, > > > >>> > > > > > > > >> > and > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > > > transaction > > > >>> > > > > > > > >> > > > > > > > > > > > state is reloaded, we need > the > > > new > > > >>> > > > producer > > > >>> > > > > ID > > > >>> > > > > > > in > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > state > > > >>> > > > > > > > >> > > > > so > > > >>> > > > > > > > >> > > > > > > > there > > > >>> > > > > > > > >> > > > > > > > > > > isn't > > > >>> > > > > > > > >> > > > > > > > > > > > an invalid producer ID > > mapping. > > > >>> > > > > > > > >> > > > > > > > > > > > The server downgrade cases > are > > > >>> > > considering > > > >>> > > > > > > > >> > transactional > > > >>> > > > > > > > >> > > > > > > > correctness > > > >>> > > > > > > > >> > > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > not regressing from previous > > > >>> behavior > > > >>> > -- > > > >>> > > > and > > > >>> > > > > > are > > > >>> > > > > > > > not > > > >>> > > > > > > > >> > > > > concerned > > > >>> > > > > > > > >> > > > > > > > about > > > >>> > > > > > > > >> > > > > > > > > > > > supporting the safety from > > > fencing > > > >>> > > retries > > > >>> > > > > (as > > > >>> > > > > > > we > > > >>> > > > > > > > >> have > > > >>> > > > > > > > >> > > > > > downgraded > > > >>> > > > > > > > >> > > > > > > > so > > > >>> > > > > > > > >> > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > don't need to support). > > Perhaps > > > >>> this > > > >>> > is > > > >>> > > a > > > >>> > > > > > trade > > > >>> > > > > > > > off, > > > >>> > > > > > > > >> > but > > > >>> > > > > > > > >> > > I > > > >>> > > > > > > > >> > > > > > think > > > >>> > > > > > > > >> > > > > > > it > > > >>> > > > > > > > >> > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > right one. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > (If the client downgrades, > it > > > will > > > >>> > have > > > >>> > > > > > > restarted > > > >>> > > > > > > > >> and > > > >>> > > > > > > > >> > it > > > >>> > > > > > > > >> > > is > > > >>> > > > > > > > >> > > > > ok > > > >>> > > > > > > > >> > > > > > > for > > > >>> > > > > > > > >> > > > > > > > it > > > >>> > > > > > > > >> > > > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > > > > have a new producer ID too). > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > Justine > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > On Fri, Jan 12, 2024 at > > 11:42 AM > > > >>> Jun > > > >>> > Rao > > > >>> > > > > > > > >> > > > > > > <j...@confluent.io.invalid > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > Thanks for the reply. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > 101.4 "If the marker is > > > written > > > >>> by > > > >>> > the > > > >>> > > > new > > > >>> > > > > > > > >> client, we > > > >>> > > > > > > > >> > > can > > > >>> > > > > > > > >> > > > > as > > > >>> > > > > > > > >> > > > > > I > > > >>> > > > > > > > >> > > > > > > > > > > mentioned > > > >>> > > > > > > > >> > > > > > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > > > > the last email guarantee > > that > > > >>> any > > > >>> > > EndTxn > > > >>> > > > > > > > requests > > > >>> > > > > > > > >> > with > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > same > > > >>> > > > > > > > >> > > > > > > > > epoch > > > >>> > > > > > > > >> > > > > > > > > > > are > > > >>> > > > > > > > >> > > > > > > > > > > > > from the same producer and > > the > > > >>> same > > > >>> > > > > > > transaction. > > > >>> > > > > > > > >> Then > > > >>> > > > > > > > >> > > we > > > >>> > > > > > > > >> > > > > > don't > > > >>> > > > > > > > >> > > > > > > > have > > > >>> > > > > > > > >> > > > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > > > > > return a fenced error but > > can > > > >>> handle > > > >>> > > > > > > gracefully > > > >>> > > > > > > > as > > > >>> > > > > > > > >> > > > > described > > > >>> > > > > > > > >> > > > > > in > > > >>> > > > > > > > >> > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > KIP." > > > >>> > > > > > > > >> > > > > > > > > > > > > When a delayed EndTnx > > request > > > is > > > >>> > > > > processed, > > > >>> > > > > > > the > > > >>> > > > > > > > >> txn > > > >>> > > > > > > > >> > > state > > > >>> > > > > > > > >> > > > > > could > > > >>> > > > > > > > >> > > > > > > > be > > > >>> > > > > > > > >> > > > > > > > > > > > ongoing > > > >>> > > > > > > > >> > > > > > > > > > > > > for the next txn. I guess > in > > > >>> this > > > >>> > case > > > >>> > > > we > > > >>> > > > > > > still > > > >>> > > > > > > > >> > return > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > fenced > > > >>> > > > > > > > >> > > > > > > > > > error > > > >>> > > > > > > > >> > > > > > > > > > > > for > > > >>> > > > > > > > >> > > > > > > > > > > > > the delayed request? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > 102. Sorry, my question > was > > > >>> > > inaccurate. > > > >>> > > > > What > > > >>> > > > > > > you > > > >>> > > > > > > > >> > > > described > > > >>> > > > > > > > >> > > > > is > > > >>> > > > > > > > >> > > > > > > > > > accurate. > > > >>> > > > > > > > >> > > > > > > > > > > > > "The downgrade > > compatibility I > > > >>> > mention > > > >>> > > > is > > > >>> > > > > > that > > > >>> > > > > > > > we > > > >>> > > > > > > > >> > keep > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > same > > > >>> > > > > > > > >> > > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > > > > and epoch in the main > > > >>> (non-tagged) > > > >>> > > > fields > > > >>> > > > > as > > > >>> > > > > > > we > > > >>> > > > > > > > >> did > > > >>> > > > > > > > >> > > > before > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > code > > > >>> > > > > > > > >> > > > > > > > > > on > > > >>> > > > > > > > >> > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > server side." If we want > to > > do > > > >>> this, > > > >>> > > it > > > >>> > > > > > seems > > > >>> > > > > > > > >> that we > > > >>> > > > > > > > >> > > > > should > > > >>> > > > > > > > >> > > > > > > use > > > >>> > > > > > > > >> > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > current produce Id and max > > > >>> epoch in > > > >>> > > the > > > >>> > > > > > > existing > > > >>> > > > > > > > >> > > > producerId > > > >>> > > > > > > > >> > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > > producerEpoch fields for > > both > > > >>> the > > > >>> > > > prepare > > > >>> > > > > > and > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > > > complete > > > >>> > > > > > > > >> > > > > > > > marker, > > > >>> > > > > > > > >> > > > > > > > > > > right? > > > >>> > > > > > > > >> > > > > > > > > > > > > The downgrade can happen > > after > > > >>> the > > > >>> > > > > complete > > > >>> > > > > > > > >> marker is > > > >>> > > > > > > > >> > > > > > written. > > > >>> > > > > > > > >> > > > > > > > With > > > >>> > > > > > > > >> > > > > > > > > > > what > > > >>> > > > > > > > >> > > > > > > > > > > > > you described, the > > downgraded > > > >>> > > > coordinator > > > >>> > > > > > will > > > >>> > > > > > > > see > > > >>> > > > > > > > >> > the > > > >>> > > > > > > > >> > > > new > > > >>> > > > > > > > >> > > > > > > > produce > > > >>> > > > > > > > >> > > > > > > > > Id > > > >>> > > > > > > > >> > > > > > > > > > > > > instead of the old one. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > Jun > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > On Fri, Jan 12, 2024 at > > > 10:44 AM > > > >>> > > Justine > > > >>> > > > > > > Olshan > > > >>> > > > > > > > >> > > > > > > > > > > > > > > <jols...@confluent.io.invalid > > > > > > > >>> > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > Hi Jun, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > I can update the > > > description. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > I believe your second > > point > > > is > > > >>> > > > mentioned > > > >>> > > > > > in > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > KIP. > > > >>> > > > > > > > >> > > I > > > >>> > > > > > > > >> > > > > can > > > >>> > > > > > > > >> > > > > > > add > > > >>> > > > > > > > >> > > > > > > > > more > > > >>> > > > > > > > >> > > > > > > > > > > > text > > > >>> > > > > > > > >> > > > > > > > > > > > > on > > > >>> > > > > > > > >> > > > > > > > > > > > > > this if it is helpful. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > The delayed message > case > > > can > > > >>> > also > > > >>> > > > > > violate > > > >>> > > > > > > > EOS > > > >>> > > > > > > > >> if > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > > delayed > > > >>> > > > > > > > >> > > > > > > > > > > message > > > >>> > > > > > > > >> > > > > > > > > > > > > > comes in after the next > > > >>> > > > > addPartitionsToTxn > > > >>> > > > > > > > >> request > > > >>> > > > > > > > >> > > > comes > > > >>> > > > > > > > >> > > > > > in. > > > >>> > > > > > > > >> > > > > > > > > > > > Effectively > > > >>> > > > > > > > >> > > > > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > > may see a message from a > > > >>> previous > > > >>> > > > > > (aborted) > > > >>> > > > > > > > >> > > transaction > > > >>> > > > > > > > >> > > > > > > become > > > >>> > > > > > > > >> > > > > > > > > part > > > >>> > > > > > > > >> > > > > > > > > > > of > > > >>> > > > > > > > >> > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > next transaction. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > If the marker is written > > by > > > >>> the > > > >>> > new > > > >>> > > > > > client, > > > >>> > > > > > > we > > > >>> > > > > > > > >> can > > > >>> > > > > > > > >> > > as I > > > >>> > > > > > > > >> > > > > > > > mentioned > > > >>> > > > > > > > >> > > > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > last email guarantee > that > > > any > > > >>> > EndTxn > > > >>> > > > > > > requests > > > >>> > > > > > > > >> with > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > same > > > >>> > > > > > > > >> > > > > > > > epoch > > > >>> > > > > > > > >> > > > > > > > > > are > > > >>> > > > > > > > >> > > > > > > > > > > > > from > > > >>> > > > > > > > >> > > > > > > > > > > > > > the same producer and > the > > > same > > > >>> > > > > > transaction. > > > >>> > > > > > > > >> Then we > > > >>> > > > > > > > >> > > > don't > > > >>> > > > > > > > >> > > > > > > have > > > >>> > > > > > > > >> > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > > > > return > > > >>> > > > > > > > >> > > > > > > > > > > > > a > > > >>> > > > > > > > >> > > > > > > > > > > > > > fenced error but can > > handle > > > >>> > > gracefully > > > >>> > > > > as > > > >>> > > > > > > > >> described > > > >>> > > > > > > > >> > > in > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > KIP. > > > >>> > > > > > > > >> > > > > > > > > > > > > > I don't think a boolean > is > > > >>> useful > > > >>> > > > since > > > >>> > > > > it > > > >>> > > > > > > is > > > >>> > > > > > > > >> > > directly > > > >>> > > > > > > > >> > > > > > > encoded > > > >>> > > > > > > > >> > > > > > > > by > > > >>> > > > > > > > >> > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > existence or lack of the > > > >>> tagged > > > >>> > > field > > > >>> > > > > > being > > > >>> > > > > > > > >> > written. > > > >>> > > > > > > > >> > > > > > > > > > > > > > In the prepare marker we > > > will > > > >>> have > > > >>> > > the > > > >>> > > > > > same > > > >>> > > > > > > > >> > producer > > > >>> > > > > > > > >> > > ID > > > >>> > > > > > > > >> > > > > in > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > non-tagged > > > >>> > > > > > > > >> > > > > > > > > > > > > > field. In the Complete > > state > > > >>> we > > > >>> > may > > > >>> > > > not. > > > >>> > > > > > > > >> > > > > > > > > > > > > > I'm not sure why the > > ongoing > > > >>> state > > > >>> > > > > matters > > > >>> > > > > > > for > > > >>> > > > > > > > >> this > > > >>> > > > > > > > >> > > > KIP. > > > >>> > > > > > > > >> > > > > It > > > >>> > > > > > > > >> > > > > > > > does > > > >>> > > > > > > > >> > > > > > > > > > > matter > > > >>> > > > > > > > >> > > > > > > > > > > > > for > > > >>> > > > > > > > >> > > > > > > > > > > > > > KIP-939. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > I'm not sure what you > are > > > >>> > referring > > > >>> > > to > > > >>> > > > > > about > > > >>> > > > > > > > >> > writing > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > previous > > > >>> > > > > > > > >> > > > > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > > > ID in the prepare > marker. > > > >>> This is > > > >>> > > not > > > >>> > > > in > > > >>> > > > > > the > > > >>> > > > > > > > >> KIP. > > > >>> > > > > > > > >> > > > > > > > > > > > > > In the overflow case, we > > > >>> write the > > > >>> > > > > > > > >> nextProducerId > > > >>> > > > > > > > >> > in > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > prepare > > > >>> > > > > > > > >> > > > > > > > > > > state. > > > >>> > > > > > > > >> > > > > > > > > > > > > > This is so we know what > we > > > >>> > assigned > > > >>> > > > when > > > >>> > > > > > we > > > >>> > > > > > > > >> reload > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > > > > transaction > > > >>> > > > > > > > >> > > > > > > > > > > log. > > > >>> > > > > > > > >> > > > > > > > > > > > > > Once we complete, we > > > >>> transition > > > >>> > this > > > >>> > > > ID > > > >>> > > > > to > > > >>> > > > > > > the > > > >>> > > > > > > > >> main > > > >>> > > > > > > > >> > > > > > > (non-tagged > > > >>> > > > > > > > >> > > > > > > > > > > field) > > > >>> > > > > > > > >> > > > > > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > > > have the previous > producer > > > ID > > > >>> > field > > > >>> > > > > filled > > > >>> > > > > > > in. > > > >>> > > > > > > > >> This > > > >>> > > > > > > > >> > > is > > > >>> > > > > > > > >> > > > so > > > >>> > > > > > > > >> > > > > > we > > > >>> > > > > > > > >> > > > > > > > can > > > >>> > > > > > > > >> > > > > > > > > > > > identify > > > >>> > > > > > > > >> > > > > > > > > > > > > > in a retry case the > > > operation > > > >>> > > > completed > > > >>> > > > > > > > >> > successfully > > > >>> > > > > > > > >> > > > and > > > >>> > > > > > > > >> > > > > we > > > >>> > > > > > > > >> > > > > > > > don't > > > >>> > > > > > > > >> > > > > > > > > > > fence > > > >>> > > > > > > > >> > > > > > > > > > > > > our > > > >>> > > > > > > > >> > > > > > > > > > > > > > producer. The downgrade > > > >>> > > compatibility > > > >>> > > > I > > > >>> > > > > > > > mention > > > >>> > > > > > > > >> is > > > >>> > > > > > > > >> > > that > > > >>> > > > > > > > >> > > > > we > > > >>> > > > > > > > >> > > > > > > keep > > > >>> > > > > > > > >> > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > same > > > >>> > > > > > > > >> > > > > > > > > > > > > > producer ID and epoch in > > the > > > >>> main > > > >>> > > > > > > (non-tagged) > > > >>> > > > > > > > >> > fields > > > >>> > > > > > > > >> > > > as > > > >>> > > > > > > > >> > > > > we > > > >>> > > > > > > > >> > > > > > > did > > > >>> > > > > > > > >> > > > > > > > > > > before > > > >>> > > > > > > > >> > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > code on the server side. > > If > > > >>> the > > > >>> > > server > > > >>> > > > > > > > >> downgrades, > > > >>> > > > > > > > >> > we > > > >>> > > > > > > > >> > > > are > > > >>> > > > > > > > >> > > > > > > still > > > >>> > > > > > > > >> > > > > > > > > > > > > compatible. > > > >>> > > > > > > > >> > > > > > > > > > > > > > This addresses both the > > > >>> prepare > > > >>> > and > > > >>> > > > > > complete > > > >>> > > > > > > > >> state > > > >>> > > > > > > > >> > > > > > > downgrades. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > Justine > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > On Fri, Jan 12, 2024 at > > > >>> 10:21 AM > > > >>> > Jun > > > >>> > > > Rao > > > >>> > > > > > > > >> > > > > > > > > <j...@confluent.io.invalid > > > >>> > > > > > > > >> > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > Thanks for the reply. > > > Sorry > > > >>> for > > > >>> > > the > > > >>> > > > > > > delay. I > > > >>> > > > > > > > >> > have a > > > >>> > > > > > > > >> > > > few > > > >>> > > > > > > > >> > > > > > > more > > > >>> > > > > > > > >> > > > > > > > > > > > comments. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > 110. I think the > > > motivation > > > >>> > > section > > > >>> > > > > > could > > > >>> > > > > > > be > > > >>> > > > > > > > >> > > > improved. > > > >>> > > > > > > > >> > > > > > One > > > >>> > > > > > > > >> > > > > > > of > > > >>> > > > > > > > >> > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > motivations listed by > > the > > > >>> KIP is > > > >>> > > > "This > > > >>> > > > > > can > > > >>> > > > > > > > >> happen > > > >>> > > > > > > > >> > > > when > > > >>> > > > > > > > >> > > > > a > > > >>> > > > > > > > >> > > > > > > > > message > > > >>> > > > > > > > >> > > > > > > > > > > gets > > > >>> > > > > > > > >> > > > > > > > > > > > > > stuck > > > >>> > > > > > > > >> > > > > > > > > > > > > > > or delayed due to > > > networking > > > >>> > > issues > > > >>> > > > > or a > > > >>> > > > > > > > >> network > > > >>> > > > > > > > >> > > > > > partition, > > > >>> > > > > > > > >> > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > transaction > > > >>> > > > > > > > >> > > > > > > > > > > > > > > aborts, and then the > > > delayed > > > >>> > > message > > > >>> > > > > > > finally > > > >>> > > > > > > > >> > comes > > > >>> > > > > > > > >> > > > > in.". > > > >>> > > > > > > > >> > > > > > > This > > > >>> > > > > > > > >> > > > > > > > > > seems > > > >>> > > > > > > > >> > > > > > > > > > > > not > > > >>> > > > > > > > >> > > > > > > > > > > > > > > very accurate. Without > > > >>> KIP-890, > > > >>> > > > > > currently, > > > >>> > > > > > > > if > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > > > > > coordinator > > > >>> > > > > > > > >> > > > > > > > > > times > > > >>> > > > > > > > >> > > > > > > > > > > > out > > > >>> > > > > > > > >> > > > > > > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > > > > aborts an ongoing > > > >>> transaction, > > > >>> > it > > > >>> > > > > > already > > > >>> > > > > > > > >> bumps > > > >>> > > > > > > > >> > up > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > epoch > > > >>> > > > > > > > >> > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > marker, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > which prevents the > > delayed > > > >>> > produce > > > >>> > > > > > message > > > >>> > > > > > > > >> from > > > >>> > > > > > > > >> > > being > > > >>> > > > > > > > >> > > > > > added > > > >>> > > > > > > > >> > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > user > > > >>> > > > > > > > >> > > > > > > > > > > > > > > partition. What can > > cause > > > a > > > >>> > > hanging > > > >>> > > > > > > > >> transaction > > > >>> > > > > > > > >> > is > > > >>> > > > > > > > >> > > > that > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > > > > completes (either > aborts > > > or > > > >>> > > > commits) a > > > >>> > > > > > > > >> > transaction > > > >>> > > > > > > > >> > > > > before > > > >>> > > > > > > > >> > > > > > > > > > > receiving a > > > >>> > > > > > > > >> > > > > > > > > > > > > > > successful ack on > > messages > > > >>> > > published > > > >>> > > > > in > > > >>> > > > > > > the > > > >>> > > > > > > > >> same > > > >>> > > > > > > > >> > > txn. > > > >>> > > > > > > > >> > > > > In > > > >>> > > > > > > > >> > > > > > > this > > > >>> > > > > > > > >> > > > > > > > > > case, > > > >>> > > > > > > > >> > > > > > > > > > > > > it's > > > >>> > > > > > > > >> > > > > > > > > > > > > > > possible for the > delayed > > > >>> message > > > >>> > > to > > > >>> > > > be > > > >>> > > > > > > > >> appended > > > >>> > > > > > > > >> > to > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > > partition > > > >>> > > > > > > > >> > > > > > > > > > > > after > > > >>> > > > > > > > >> > > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > marker, causing a > > > >>> transaction to > > > >>> > > > hang. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > A similar issue (not > > > >>> mentioned > > > >>> > in > > > >>> > > > the > > > >>> > > > > > > > >> motivation) > > > >>> > > > > > > > >> > > > could > > > >>> > > > > > > > >> > > > > > > > happen > > > >>> > > > > > > > >> > > > > > > > > on > > > >>> > > > > > > > >> > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > marker in the > > > coordinator's > > > >>> log. > > > >>> > > For > > > >>> > > > > > > > example, > > > >>> > > > > > > > >> > it's > > > >>> > > > > > > > >> > > > > > possible > > > >>> > > > > > > > >> > > > > > > > for > > > >>> > > > > > > > >> > > > > > > > > > an > > > >>> > > > > > > > >> > > > > > > > > > > > > > > EndTxnRequest to be > > > delayed > > > >>> on > > > >>> > the > > > >>> > > > > > > > >> coordinator. > > > >>> > > > > > > > >> > By > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > time > > > >>> > > > > > > > >> > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > delayed > > > >>> > > > > > > > >> > > > > > > > > > > > > > > EndTxnRequest is > > > processed, > > > >>> it's > > > >>> > > > > > possible > > > >>> > > > > > > > that > > > >>> > > > > > > > >> > the > > > >>> > > > > > > > >> > > > > > previous > > > >>> > > > > > > > >> > > > > > > > txn > > > >>> > > > > > > > >> > > > > > > > > > has > > > >>> > > > > > > > >> > > > > > > > > > > > > > already > > > >>> > > > > > > > >> > > > > > > > > > > > > > > completed and a new > txn > > > has > > > >>> > > started. > > > >>> > > > > > > > >> Currently, > > > >>> > > > > > > > >> > > since > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > epoch > > > >>> > > > > > > > >> > > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > not > > > >>> > > > > > > > >> > > > > > > > > > > > > > > bumped on every txn, > the > > > >>> delayed > > > >>> > > > > > > > EndTxnRequest > > > >>> > > > > > > > >> > will > > > >>> > > > > > > > >> > > > add > > > >>> > > > > > > > >> > > > > > an > > > >>> > > > > > > > >> > > > > > > > > > > unexpected > > > >>> > > > > > > > >> > > > > > > > > > > > > > > prepare marker (and > > > >>> eventually a > > > >>> > > > > > complete > > > >>> > > > > > > > >> marker) > > > >>> > > > > > > > >> > > to > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > > ongoing > > > >>> > > > > > > > >> > > > > > > > > > > txn. > > > >>> > > > > > > > >> > > > > > > > > > > > > > This > > > >>> > > > > > > > >> > > > > > > > > > > > > > > won't cause the > > > transaction > > > >>> to > > > >>> > > hang, > > > >>> > > > > but > > > >>> > > > > > > it > > > >>> > > > > > > > >> will > > > >>> > > > > > > > >> > > > break > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > EoS > > > >>> > > > > > > > >> > > > > > > > > > > > > semantic. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > The proposal in this > KIP > > > >>> will > > > >>> > > > address > > > >>> > > > > > this > > > >>> > > > > > > > >> issue > > > >>> > > > > > > > >> > > too. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > 101. "However, I was > > > >>> writing it > > > >>> > so > > > >>> > > > > that > > > >>> > > > > > we > > > >>> > > > > > > > can > > > >>> > > > > > > > >> > > > > > distinguish > > > >>> > > > > > > > >> > > > > > > > > > between > > > >>> > > > > > > > >> > > > > > > > > > > > > > > old clients where we > > don't > > > >>> have > > > >>> > > the > > > >>> > > > > > > ability > > > >>> > > > > > > > do > > > >>> > > > > > > > >> > this > > > >>> > > > > > > > >> > > > > > > operation > > > >>> > > > > > > > >> > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > new > > > >>> > > > > > > > >> > > > > > > > > > > > > > > clients that can. (Old > > > >>> clients > > > >>> > > don't > > > >>> > > > > > bump > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > epoch > > > >>> > > > > > > > >> > > > on > > > >>> > > > > > > > >> > > > > > > > commit, > > > >>> > > > > > > > >> > > > > > > > > so > > > >>> > > > > > > > >> > > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > > can't > > > >>> > > > > > > > >> > > > > > > > > > > > > > > say for sure the write > > > >>> belongs > > > >>> > to > > > >>> > > > the > > > >>> > > > > > > given > > > >>> > > > > > > > >> > > > > > transaction)." > > > >>> > > > > > > > >> > > > > > > > > > > > > > > 101.1 I am wondering > why > > > we > > > >>> need > > > >>> > > to > > > >>> > > > > > > > >> distinguish > > > >>> > > > > > > > >> > > > whether > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > marker > > > >>> > > > > > > > >> > > > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > > > > written by the old and > > the > > > >>> new > > > >>> > > > client. > > > >>> > > > > > > Could > > > >>> > > > > > > > >> you > > > >>> > > > > > > > >> > > > > describe > > > >>> > > > > > > > >> > > > > > > > what > > > >>> > > > > > > > >> > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > do > > > >>> > > > > > > > >> > > > > > > > > > > > > > > differently if we know > > the > > > >>> > marker > > > >>> > > is > > > >>> > > > > > > written > > > >>> > > > > > > > >> by > > > >>> > > > > > > > >> > the > > > >>> > > > > > > > >> > > > new > > > >>> > > > > > > > >> > > > > > > > client? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > 101.2 If we do need a > > way > > > to > > > >>> > > > > distinguish > > > >>> > > > > > > > >> whether > > > >>> > > > > > > > >> > > the > > > >>> > > > > > > > >> > > > > > marker > > > >>> > > > > > > > >> > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > written > > > >>> > > > > > > > >> > > > > > > > > > > > > by > > > >>> > > > > > > > >> > > > > > > > > > > > > > > the old and the new > > > client. > > > >>> > Would > > > >>> > > it > > > >>> > > > > be > > > >>> > > > > > > > >> simpler > > > >>> > > > > > > > >> > to > > > >>> > > > > > > > >> > > > just > > > >>> > > > > > > > >> > > > > > > > > > introduce a > > > >>> > > > > > > > >> > > > > > > > > > > > > > boolean > > > >>> > > > > > > > >> > > > > > > > > > > > > > > field instead of > > > indirectly > > > >>> > > through > > > >>> > > > > the > > > >>> > > > > > > > >> previous > > > >>> > > > > > > > >> > > > > produce > > > >>> > > > > > > > >> > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > field? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > 101.3 It's not clear > to > > me > > > >>> why > > > >>> > we > > > >>> > > > only > > > >>> > > > > > add > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > > > previous > > > >>> > > > > > > > >> > > > > > > > produce > > > >>> > > > > > > > >> > > > > > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > > > > field > > > >>> > > > > > > > >> > > > > > > > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > > > > > > the complete marker, > but > > > >>> not in > > > >>> > > the > > > >>> > > > > > > prepare > > > >>> > > > > > > > >> > marker. > > > >>> > > > > > > > >> > > > If > > > >>> > > > > > > > >> > > > > we > > > >>> > > > > > > > >> > > > > > > > want > > > >>> > > > > > > > >> > > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > > > > know > > > >>> > > > > > > > >> > > > > > > > > > > > > > > whether a marker is > > > written > > > >>> by > > > >>> > the > > > >>> > > > new > > > >>> > > > > > > > client > > > >>> > > > > > > > >> or > > > >>> > > > > > > > >> > > not, > > > >>> > > > > > > > >> > > > > it > > > >>> > > > > > > > >> > > > > > > > seems > > > >>> > > > > > > > >> > > > > > > > > > that > > > >>> > > > > > > > >> > > > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > > want > > > >>> > > > > > > > >> > > > > > > > > > > > > > > to do this > consistently > > > for > > > >>> all > > > >>> > > > > markers. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > 101.4 What about the > > > >>> > > > > TransactionLogValue > > > >>> > > > > > > > >> record > > > >>> > > > > > > > >> > > > > > > representing > > > >>> > > > > > > > >> > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > ongoing > > > >>> > > > > > > > >> > > > > > > > > > > > > > > state? Should we also > > > >>> > distinguish > > > >>> > > > > > whether > > > >>> > > > > > > > it's > > > >>> > > > > > > > >> > > > written > > > >>> > > > > > > > >> > > > > by > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > old > > > >>> > > > > > > > >> > > > > > > > > > > or > > > >>> > > > > > > > >> > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > new client? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > 102. In the overflow > > case, > > > >>> it's > > > >>> > > > still > > > >>> > > > > > not > > > >>> > > > > > > > >> clear > > > >>> > > > > > > > >> > to > > > >>> > > > > > > > >> > > me > > > >>> > > > > > > > >> > > > > why > > > >>> > > > > > > > >> > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > write > > > >>> > > > > > > > >> > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > previous produce Id in > > the > > > >>> > prepare > > > >>> > > > > > marker > > > >>> > > > > > > > >> while > > > >>> > > > > > > > >> > > > writing > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > > next > > > >>> > > > > > > > >> > > > > > > > > > > > > produce > > > >>> > > > > > > > >> > > > > > > > > > > > > > Id > > > >>> > > > > > > > >> > > > > > > > > > > > > > > in the complete > marker. > > > You > > > >>> > > > mentioned > > > >>> > > > > > that > > > >>> > > > > > > > >> it's > > > >>> > > > > > > > >> > for > > > >>> > > > > > > > >> > > > > > > > > downgrading. > > > >>> > > > > > > > >> > > > > > > > > > > > > However, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > we could downgrade > with > > > >>> either > > > >>> > the > > > >>> > > > > > prepare > > > >>> > > > > > > > >> marker > > > >>> > > > > > > > >> > > or > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > > complete > > > >>> > > > > > > > >> > > > > > > > > > > > > marker. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > In either case, the > > > >>> downgraded > > > >>> > > > > > coordinator > > > >>> > > > > > > > >> should > > > >>> > > > > > > > >> > > see > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > same > > > >>> > > > > > > > >> > > > > > > > > > > > produce > > > >>> > > > > > > > >> > > > > > > > > > > > > id > > > >>> > > > > > > > >> > > > > > > > > > > > > > > (probably the previous > > > >>> produce > > > >>> > > Id), > > > >>> > > > > > right? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > Jun > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > On Wed, Dec 20, 2023 > at > > > >>> 6:00 PM > > > >>> > > > > Justine > > > >>> > > > > > > > Olshan > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> <jols...@confluent.io.invalid> > > > >>> > > > > > > > >> > > > > > > > > > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > Hey Jun, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > Thanks for taking a > > look > > > >>> at > > > >>> > the > > > >>> > > > KIP > > > >>> > > > > > > again. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > 100. For the epoch > > > >>> overflow > > > >>> > > case, > > > >>> > > > > only > > > >>> > > > > > > the > > > >>> > > > > > > > >> > marker > > > >>> > > > > > > > >> > > > > will > > > >>> > > > > > > > >> > > > > > > have > > > >>> > > > > > > > >> > > > > > > > > max > > > >>> > > > > > > > >> > > > > > > > > > > > > epoch. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > This > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > keeps the behavior > of > > > the > > > >>> rest > > > >>> > > of > > > >>> > > > > the > > > >>> > > > > > > > >> markers > > > >>> > > > > > > > >> > > where > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > last > > > >>> > > > > > > > >> > > > > > > > > > > marker > > > >>> > > > > > > > >> > > > > > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > epoch of the > > transaction > > > >>> > > records + > > > >>> > > > > 1. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > 101. You are correct > > > that > > > >>> we > > > >>> > > don't > > > >>> > > > > > need > > > >>> > > > > > > to > > > >>> > > > > > > > >> > write > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > > > > since > > > >>> > > > > > > > >> > > > > > > > > > > > > > it > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > is the same. > However, > > I > > > >>> was > > > >>> > > > writing > > > >>> > > > > it > > > >>> > > > > > > so > > > >>> > > > > > > > >> that > > > >>> > > > > > > > >> > we > > > >>> > > > > > > > >> > > > can > > > >>> > > > > > > > >> > > > > > > > > > distinguish > > > >>> > > > > > > > >> > > > > > > > > > > > > > between > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > old clients where we > > > don't > > > >>> > have > > > >>> > > > the > > > >>> > > > > > > > ability > > > >>> > > > > > > > >> do > > > >>> > > > > > > > >> > > this > > > >>> > > > > > > > >> > > > > > > > operation > > > >>> > > > > > > > >> > > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > new > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > clients that can. > (Old > > > >>> clients > > > >>> > > > don't > > > >>> > > > > > > bump > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > epoch > > > >>> > > > > > > > >> > > > > on > > > >>> > > > > > > > >> > > > > > > > > commit, > > > >>> > > > > > > > >> > > > > > > > > > so > > > >>> > > > > > > > >> > > > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > > > can't > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > say for sure the > write > > > >>> belongs > > > >>> > > to > > > >>> > > > > the > > > >>> > > > > > > > given > > > >>> > > > > > > > >> > > > > > transaction). > > > >>> > > > > > > > >> > > > > > > > If > > > >>> > > > > > > > >> > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > receive > > > >>> > > > > > > > >> > > > > > > > > > > > > > > an > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > EndTxn request from > a > > > new > > > >>> > > client, > > > >>> > > > we > > > >>> > > > > > > will > > > >>> > > > > > > > >> fill > > > >>> > > > > > > > >> > > this > > > >>> > > > > > > > >> > > > > > > field. > > > >>> > > > > > > > >> > > > > > > > We > > > >>> > > > > > > > >> > > > > > > > > > can > > > >>> > > > > > > > >> > > > > > > > > > > > > > > guarantee > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > that any EndTxn > > requests > > > >>> with > > > >>> > > the > > > >>> > > > > same > > > >>> > > > > > > > epoch > > > >>> > > > > > > > >> > are > > > >>> > > > > > > > >> > > > from > > > >>> > > > > > > > >> > > > > > the > > > >>> > > > > > > > >> > > > > > > > > same > > > >>> > > > > > > > >> > > > > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > the same > transaction. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > 102. In prepare > phase, > > > we > > > >>> have > > > >>> > > the > > > >>> > > > > > same > > > >>> > > > > > > > >> > producer > > > >>> > > > > > > > >> > > ID > > > >>> > > > > > > > >> > > > > and > > > >>> > > > > > > > >> > > > > > > > epoch > > > >>> > > > > > > > >> > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > always > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > had. It is the > > producer > > > >>> ID and > > > >>> > > > epoch > > > >>> > > > > > > that > > > >>> > > > > > > > >> are > > > >>> > > > > > > > >> > on > > > >>> > > > > > > > >> > > > the > > > >>> > > > > > > > >> > > > > > > > marker. > > > >>> > > > > > > > >> > > > > > > > > In > > > >>> > > > > > > > >> > > > > > > > > > > > > commit > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > phase, we stay the > > same > > > >>> unless > > > >>> > > it > > > >>> > > > is > > > >>> > > > > > the > > > >>> > > > > > > > >> > overflow > > > >>> > > > > > > > >> > > > > case. > > > >>> > > > > > > > >> > > > > > > In > > > >>> > > > > > > > >> > > > > > > > > that > > > >>> > > > > > > > >> > > > > > > > > > > > case, > > > >>> > > > > > > > >> > > > > > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > set the producer ID > to > > > >>> the new > > > >>> > > one > > > >>> > > > > we > > > >>> > > > > > > > >> generated > > > >>> > > > > > > > >> > > and > > > >>> > > > > > > > >> > > > > > epoch > > > >>> > > > > > > > >> > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > 0 > > > >>> > > > > > > > >> > > > > > > > > > > > after > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > complete. This is > for > > > >>> > downgrade > > > >>> > > > > > > > >> compatibility. > > > >>> > > > > > > > >> > > The > > > >>> > > > > > > > >> > > > > > tagged > > > >>> > > > > > > > >> > > > > > > > > > fields > > > >>> > > > > > > > >> > > > > > > > > > > > are > > > >>> > > > > > > > >> > > > > > > > > > > > > > just > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > safety guards for > > > retries > > > >>> and > > > >>> > > > > > failovers. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > In prepare phase for > > > epoch > > > >>> > > > overflow > > > >>> > > > > > case > > > >>> > > > > > > > >> only > > > >>> > > > > > > > >> > we > > > >>> > > > > > > > >> > > > > store > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > next > > > >>> > > > > > > > >> > > > > > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > ID. This is for the > > case > > > >>> where > > > >>> > > we > > > >>> > > > > > reload > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > > > > > transaction > > > >>> > > > > > > > >> > > > > > > > > > > > coordinator > > > >>> > > > > > > > >> > > > > > > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > prepare state. Once > > the > > > >>> > > > transaction > > > >>> > > > > is > > > >>> > > > > > > > >> > committed, > > > >>> > > > > > > > >> > > > we > > > >>> > > > > > > > >> > > > > > can > > > >>> > > > > > > > >> > > > > > > > use > > > >>> > > > > > > > >> > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > ID the client > already > > is > > > >>> > using. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > In commit phase, we > > > store > > > >>> the > > > >>> > > > > previous > > > >>> > > > > > > > >> producer > > > >>> > > > > > > > >> > > ID > > > >>> > > > > > > > >> > > > in > > > >>> > > > > > > > >> > > > > > > case > > > >>> > > > > > > > >> > > > > > > > of > > > >>> > > > > > > > >> > > > > > > > > > > > > retries. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > I think it is easier > > to > > > >>> think > > > >>> > of > > > >>> > > > it > > > >>> > > > > as > > > >>> > > > > > > > just > > > >>> > > > > > > > >> how > > > >>> > > > > > > > >> > > we > > > >>> > > > > > > > >> > > > > were > > > >>> > > > > > > > >> > > > > > > > > storing > > > >>> > > > > > > > >> > > > > > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > and epoch before, > with > > > >>> some > > > >>> > > extra > > > >>> > > > > > > > bookeeping > > > >>> > > > > > > > >> > and > > > >>> > > > > > > > >> > > > edge > > > >>> > > > > > > > >> > > > > > > case > > > >>> > > > > > > > >> > > > > > > > > > > handling > > > >>> > > > > > > > >> > > > > > > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > tagged fields. We > have > > > to > > > >>> do > > > >>> > it > > > >>> > > > this > > > >>> > > > > > way > > > >>> > > > > > > > for > > > >>> > > > > > > > >> > > > > > > compatibility > > > >>> > > > > > > > >> > > > > > > > > with > > > >>> > > > > > > > >> > > > > > > > > > > > > > > downgrades. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > 103. Next producer > ID > > is > > > >>> for > > > >>> > > > prepare > > > >>> > > > > > > > status > > > >>> > > > > > > > >> and > > > >>> > > > > > > > >> > > > > > previous > > > >>> > > > > > > > >> > > > > > > > > > producer > > > >>> > > > > > > > >> > > > > > > > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > > > > for > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > after complete. The > > > >>> reason why > > > >>> > > we > > > >>> > > > > need > > > >>> > > > > > > two > > > >>> > > > > > > > >> > > separate > > > >>> > > > > > > > >> > > > > > > > (tagged) > > > >>> > > > > > > > >> > > > > > > > > > > fields > > > >>> > > > > > > > >> > > > > > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > > > > for > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > backwards > > compatibility. > > > >>> We > > > >>> > need > > > >>> > > > to > > > >>> > > > > > keep > > > >>> > > > > > > > the > > > >>> > > > > > > > >> > same > > > >>> > > > > > > > >> > > > > > > semantics > > > >>> > > > > > > > >> > > > > > > > > for > > > >>> > > > > > > > >> > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > non-tagged field in > > case > > > >>> we > > > >>> > > > > downgrade. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > 104. We set the > fields > > > as > > > >>> we > > > >>> > do > > > >>> > > in > > > >>> > > > > the > > > >>> > > > > > > > >> > > > transactional > > > >>> > > > > > > > >> > > > > > > state > > > >>> > > > > > > > >> > > > > > > > > (as > > > >>> > > > > > > > >> > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > need > > > >>> > > > > > > > >> > > > > > > > > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > do this for > > > compatibility > > > >>> -- > > > >>> > if > > > >>> > > we > > > >>> > > > > > > > >> downgrade, > > > >>> > > > > > > > >> > we > > > >>> > > > > > > > >> > > > will > > > >>> > > > > > > > >> > > > > > > only > > > >>> > > > > > > > >> > > > > > > > > have > > > >>> > > > > > > > >> > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > non-tagged fields) > It > > > >>> will be > > > >>> > > the > > > >>> > > > > old > > > >>> > > > > > > > >> producer > > > >>> > > > > > > > >> > ID > > > >>> > > > > > > > >> > > > and > > > >>> > > > > > > > >> > > > > > max > > > >>> > > > > > > > >> > > > > > > > > > epoch. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > Hope this helps. Let > > me > > > >>> know > > > >>> > if > > > >>> > > > you > > > >>> > > > > > have > > > >>> > > > > > > > >> > further > > > >>> > > > > > > > >> > > > > > > questions. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > Justine > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > On Wed, Dec 20, 2023 > > at > > > >>> > 3:33 PM > > > >>> > > > Jun > > > >>> > > > > > Rao > > > >>> > > > > > > > >> > > > > > > > > > <j...@confluent.io.invalid > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > wrote: > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > Hi, Justine, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > It seems that you > > have > > > >>> made > > > >>> > > some > > > >>> > > > > > > changes > > > >>> > > > > > > > >> to > > > >>> > > > > > > > >> > > > KIP-890 > > > >>> > > > > > > > >> > > > > > > since > > > >>> > > > > > > > >> > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > vote. > > > >>> > > > > > > > >> > > > > > > > > > > > > > In > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > particular, we are > > > >>> changing > > > >>> > > the > > > >>> > > > > > format > > > >>> > > > > > > > of > > > >>> > > > > > > > >> > > > > > > > > > TransactionLogValue. > > > >>> > > > > > > > >> > > > > > > > > > > A > > > >>> > > > > > > > >> > > > > > > > > > > > > few > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > comments related > to > > > >>> that. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > 100. Just to be > > clear. > > > >>> The > > > >>> > > > > overflow > > > >>> > > > > > > case > > > >>> > > > > > > > >> > (i.e. > > > >>> > > > > > > > >> > > > > when a > > > >>> > > > > > > > >> > > > > > > new > > > >>> > > > > > > > >> > > > > > > > > > > > > producerId > > > >>> > > > > > > > >> > > > > > > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > generated) is when > > the > > > >>> > current > > > >>> > > > > epoch > > > >>> > > > > > > > >> equals > > > >>> > > > > > > > >> > to > > > >>> > > > > > > > >> > > > max > > > >>> > > > > > > > >> > > > > - > > > >>> > > > > > > > >> > > > > > 1 > > > >>> > > > > > > > >> > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > not > > > >>> > > > > > > > >> > > > > > > > > > > > max? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > 101. For the "not > > > epoch > > > >>> > > > overflow" > > > >>> > > > > > > case, > > > >>> > > > > > > > we > > > >>> > > > > > > > >> > > write > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > > previous > > > >>> > > > > > > > >> > > > > > > > > > > ID > > > >>> > > > > > > > >> > > > > > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > tagged field in > the > > > >>> complete > > > >>> > > > > phase. > > > >>> > > > > > Do > > > >>> > > > > > > > we > > > >>> > > > > > > > >> > need > > > >>> > > > > > > > >> > > to > > > >>> > > > > > > > >> > > > > do > > > >>> > > > > > > > >> > > > > > > that > > > >>> > > > > > > > >> > > > > > > > > > since > > > >>> > > > > > > > >> > > > > > > > > > > > > > produce > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > id > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > doesn't change in > > this > > > >>> case? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > 102. It seems that > > the > > > >>> > meaning > > > >>> > > > for > > > >>> > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > ProducerId/ProducerEpoch > > > >>> > > > > > > > >> > > > > > > > > > > > > > fields > > > >>> > > > > > > > >> > > > > > > > > > > > > > > in > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > TransactionLogValue > > > >>> changes > > > >>> > > > > > depending > > > >>> > > > > > > on > > > >>> > > > > > > > >> the > > > >>> > > > > > > > >> > > > > > > > > > TransactionStatus. > > > >>> > > > > > > > >> > > > > > > > > > > > > When > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > the > > TransactionStatus > > > is > > > >>> > > > ongoing, > > > >>> > > > > > they > > > >>> > > > > > > > >> > > represent > > > >>> > > > > > > > >> > > > > the > > > >>> > > > > > > > >> > > > > > > > > current > > > >>> > > > > > > > >> > > > > > > > > > > > > > ProducerId > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > the current > > > >>> ProducerEpoch. > > > >>> > > When > > > >>> > > > > the > > > >>> > > > > > > > >> > > > > TransactionStatus > > > >>> > > > > > > > >> > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> PrepareCommit/PrepareAbort, > > > >>> > > they > > > >>> > > > > > > > represent > > > >>> > > > > > > > >> > the > > > >>> > > > > > > > >> > > > > > current > > > >>> > > > > > > > >> > > > > > > > > > > ProducerId > > > >>> > > > > > > > >> > > > > > > > > > > > > and > > > >>> > > > > > > > >> > > > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > next > ProducerEpoch. > > > >>> When the > > > >>> > > > > > > > >> > TransactionStatus > > > >>> > > > > > > > >> > > is > > > >>> > > > > > > > >> > > > > > > > > > Commit/Abort, > > > >>> > > > > > > > >> > > > > > > > > > > > > they > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > further depend on > > > >>> whether > > > >>> > the > > > >>> > > > > epoch > > > >>> > > > > > > > >> overflows > > > >>> > > > > > > > >> > > or > > > >>> > > > > > > > >> > > > > not. > > > >>> > > > > > > > >> > > > > > > If > > > >>> > > > > > > > >> > > > > > > > > > there > > > >>> > > > > > > > >> > > > > > > > > > > is > > > >>> > > > > > > > >> > > > > > > > > > > > > no > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > overflow, they > > > represent > > > >>> > the > > > >>> > > > > > current > > > >>> > > > > > > > >> > > ProducerId > > > >>> > > > > > > > >> > > > > and > > > >>> > > > > > > > >> > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > next > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > ProducerEpoch > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > (max). Otherwise, > > they > > > >>> > > represent > > > >>> > > > > the > > > >>> > > > > > > > newly > > > >>> > > > > > > > >> > > > > generated > > > >>> > > > > > > > >> > > > > > > > > > ProducerId > > > >>> > > > > > > > >> > > > > > > > > > > > > and a > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > ProducerEpoch of > 0. > > Is > > > >>> that > > > >>> > > > right? > > > >>> > > > > > > This > > > >>> > > > > > > > >> seems > > > >>> > > > > > > > >> > > not > > > >>> > > > > > > > >> > > > > > easy > > > >>> > > > > > > > >> > > > > > > to > > > >>> > > > > > > > >> > > > > > > > > > > > > understand. > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > Could > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > we provide some > > > examples > > > >>> > like > > > >>> > > > what > > > >>> > > > > > > Artem > > > >>> > > > > > > > >> has > > > >>> > > > > > > > >> > > done > > > >>> > > > > > > > >> > > > > in > > > >>> > > > > > > > >> > > > > > > > > KIP-939? > > > >>> > > > > > > > >> > > > > > > > > > > > Have > > > >>> > > > > > > > >> > > > > > > > > > > > > we > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > considered a > simpler > > > >>> design > > > >>> > > > where > > > >>> > > > > > > > >> > > > > > > > ProducerId/ProducerEpoch > > > >>> > > > > > > > >> > > > > > > > > > > always > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > represent > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > the same value > (e.g. > > > >>> for the > > > >>> > > > > current > > > >>> > > > > > > > >> > > transaction) > > > >>> > > > > > > > >> > > > > > > > > independent > > > >>> > > > > > > > >> > > > > > > > > > > of > > > >>> > > > > > > > >> > > > > > > > > > > > > the > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > TransactionStatus > > and > > > >>> epoch > > > >>> > > > > > overflow? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > 103. It's not > clear > > to > > > >>> me > > > >>> > why > > > >>> > > we > > > >>> > > > > > need > > > >>> > > > > > > 3 > > > >>> > > > > > > > >> > fields: > > > >>> > > > > > > > >> > > > > > > > ProducerId, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > PrevProducerId, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > NextProducerId. > > Could > > > we > > > >>> > just > > > >>> > > > have > > > >>> > > > > > > > >> ProducerId > > > >>> > > > > > > > >> > > and > > > >>> > > > > > > > >> > > > > > > > > > > NextProducerId? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > 104. For > > > >>> > > WriteTxnMarkerRequests, > > > >>> > > > > if > > > >>> > > > > > > the > > > >>> > > > > > > > >> > > producer > > > >>> > > > > > > > >> > > > > > epoch > > > >>> > > > > > > > >> > > > > > > > > > > overflows, > > > >>> > > > > > > > >> > > > > > > > > > > > > > what > > > >>> > > > > > > > >> > > > > > > > > > > > > > > do > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > we set the > > producerId > > > >>> and > > > >>> > the > > > >>> > > > > > > > >> producerEpoch? > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > Thanks, > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > Jun > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > > >>> > > > > > > > >> > > > > > > > > > >>> > > > > > > > >> > > > > > > > > >>> > > > > > > > >> > > > > > > > >>> > > > > > > > >> > > > > > > >>> > > > > > > > >> > > > > > >>> > > > > > > > >> > > > > >>> > > > > > > > >> > > > >>> > > > > > > > > > > > >>> > > > > > > > > > > >>> > > > > > > > > > >>> > > > > > > > > >>> > > > > > > > >>> > > > > > > >>> > > > > > >>> > > > > >>> > > > >> > > > > > >
