Right now, we don't need the value length: since it is the last item in the message, and we have the message length, we can deduce the value length. However, if we are adding record headers to the end, we would need to introduce the value length along with that change.
On Tue, Feb 21, 2017 at 3:34 PM, Michael Pearce <michael.pea...@ig.com> wrote: > It seems I cannot add comment on the doc. > > In the section around the message protocol. > > It has stated: > > Message => > Length => uintVar > Attributes => int8 > TimestampDelta => intVar > OffsetDelta => uintVar > KeyLen => uintVar [OPTIONAL] > Key => data [OPTIONAL] > Value => data [OPTIONAL] > > Should it not be: (added missing value len) > > Message => > Length => uintVar > Attributes => int8 > TimestampDelta => intVar > OffsetDelta => uintVar > KeyLen => uintVar [OPTIONAL] > Key => data [OPTIONAL] > ValueLen => uintVar [OPTIONAL] > Value => data [OPTIONAL] > > > > On 21/02/2017, 23:07, "Joel Koshy" <jjkosh...@gmail.com> wrote: > > I left a couple of comments/questions directly on the google-doc > <https://docs.google.com/document/d/11Jqy_ > GjUGtdXJK94XGsEIK7CP1SnQGdp2eF0wSw9ra8> > - I found it much more tractable for a proposal of this size to > discuss in > context within the doc. The permissions on the doc don't let everyone > view > comments, so if there are any material changes that come out of the > discussions in those comment threads we can summarize here. > > Thanks, > > Joel > > On Mon, Feb 20, 2017 at 4:08 PM, Becket Qin <becket....@gmail.com> > wrote: > > > Thanks for the explanation, Guozhang. That makes sense. > > > > On Sun, Feb 19, 2017 at 7:28 PM, Guozhang Wang <wangg...@gmail.com> > wrote: > > > > > Thanks Becket. > > > > > > Actually sequence is associated with a message, not a message set. > For > > > example if a message set sent by producer contains 100 messages, > and the > > > first message's sequence is 5, then the last message's sequence > number > > > would be 104, and the next message set's first sequence is > expected to be > > > 105. > > > > > > > > > Guozhang > > > > > > > > > On Sun, Feb 19, 2017 at 4:48 PM, Becket Qin <becket....@gmail.com> > > wrote: > > > > > > > +1. Thanks for the great work on the KIP! > > > > > > > > I have only one minor question, in the wiki (and the doc) the new > > message > > > > set format has a "FirstSequence" field, should it just be > "Sequence" if > > > the > > > > sequence is always associated with a message set? > > > > > > > > On Fri, Feb 17, 2017 at 3:28 AM, Michael Pearce < > michael.pea...@ig.com > > > > > > > wrote: > > > > > > > > > +0 > > > > > > > > > > I think need some unified agreement on the VarInts. > > > > > > > > > > Would this also change in all other area’s of the protocol, > e.g. > > value > > > > and > > > > > key length in message protocol, to keep this uniform across all > > > protocols > > > > > going forwards? > > > > > > > > > > > > > > > > > > > > On 17/02/2017, 00:23, "Apurva Mehta" <apu...@confluent.io> > wrote: > > > > > > > > > > Hi Jun, > > > > > > > > > > Thanks for the reply. Comments inline. > > > > > > > > > > On Thu, Feb 16, 2017 at 2:29 PM, Jun Rao <j...@confluent.io > > > > wrote: > > > > > > > > > > > Hi, Apurva, > > > > > > > > > > > > Thanks for the reply. A couple of comment below. > > > > > > > > > > > > On Wed, Feb 15, 2017 at 9:45 PM, Apurva Mehta < > > > apu...@confluent.io > > > > > > > > > > wrote: > > > > > > > > > > > > > Hi Jun, > > > > > > > > > > > > > > Answers inline: > > > > > > > > > > > > > > 210. Pid snapshots: Is the number of pid snapshot > > configurable > > > or > > > > > > hardcoded > > > > > > > > with 2? When do we decide to roll a new snapshot? > Based on > > > > time, > > > > > byte, > > > > > > or > > > > > > > > offset? Is that configurable too? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > When a replica becomes a follower, we do a bit log > truncation. > > > > > Having an > > > > > > older snapshot allows us to recover the PID->sequence > mapping > > > much > > > > > quicker > > > > > > than rescanning the whole log. > > > > > > > > > > > > > > > This is a good point. I have updated the doc with a more > detailed > > > > > proposal. > > > > > Essentially, snapshots will be created on a periodic > basis. A > > > > > reasonable > > > > > period would be every 30 or 60 seconds. We will keep at > most 2 > > > copies > > > > > of > > > > > the snapshot file. With this setup, we would have to > replay at > > most > > > > 60 > > > > > or > > > > > 120 seconds of the log in the event of log truncation > during > > leader > > > > > failover. > > > > > > > > > > If we need to make any of this configurable, we can expose > a > > config > > > > in > > > > > the > > > > > future. It would be easier to add a config we need than > remove > > one > > > > with > > > > > marginal utility. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 211. I am wondering if we should store > ExpirationTime in > > the > > > > > producer > > > > > > > > transactionalId mapping message as we do in the > producer > > > > > transaction > > > > > > > status > > > > > > > > message. If a producer only calls > initTransactions(), but > > > never > > > > > > publishes > > > > > > > > any data, we still want to be able to expire and > remove the > > > > > producer > > > > > > > > transactionalId mapping message. > > > > > > > > > > > > > > > > > > > > > > > Actually, the document was inaccurate. The > transactionalId > > will > > > > be > > > > > > expired > > > > > > > only if there is no active transaction, and the age of > the > > last > > > > > > transaction > > > > > > > with that transactionalId is older than the > transactioanlId > > > > > expiration > > > > > > > time. With these semantics, storing the expiration > time in > > the > > > > > > > transactionalId mapping message won't be useful, since > the > > > > > expiration > > > > > > time > > > > > > > is a moving target based on transaction activity. > > > > > > > > > > > > > > I have updated the doc with a clarification. > > > > > > > > > > > > > > > > > > > > > > > > > > > Currently, the producer transactionalId mapping message > doesn't > > > > carry > > > > > > ExpirationTime, but the producer transaction status > message > > does. > > > > > It would > > > > > > be useful if they are consistent. > > > > > > > > > > > > > > > > > You are right. The document has been updated to remove the > > > > > ExpirationTime > > > > > from the transaction status messages as well. Any utility > for > > this > > > > > field > > > > > can be achieved by using the timestamp of the message > itself > > along > > > > with > > > > > another expiration time (like transactionalId expiration > time, > > > > > transaction > > > > > expiration time, etc.). > > > > > > > > > > Thanks, > > > > > Apurva > > > > > > > > > > > > > > > The information contained in this email is strictly > confidential and > > > for > > > > > the use of the addressee only, unless otherwise indicated. If > you are > > > not > > > > > the intended recipient, please do not read, copy, use or > disclose to > > > > others > > > > > this message or any attachment. Please also notify the sender > by > > > replying > > > > > to this email or by telephone (+44(020 7896 0011) and then > delete the > > > > email > > > > > and any copies of it. Opinions, conclusion (etc) that do not > relate > > to > > > > the > > > > > official business of this company shall be understood as > neither > > given > > > > nor > > > > > endorsed by it. IG is a trading name of IG Markets Limited (a > company > > > > > registered in England and Wales, company number 04008957) and > IG > > Index > > > > > Limited (a company registered in England and Wales, company > number > > > > > 01190902). Registered address at Cannon Bridge House, 25 > Dowgate > > Hill, > > > > > London EC4R 2YA. Both IG Markets Limited (register number > 195355) and > > > IG > > > > > Index Limited (register number 114059) are authorised and > regulated > > by > > > > the > > > > > Financial Conduct Authority. > > > > > > > > > > > > > > > > > > > > > -- > > > -- Guozhang > > > > > > > > The information contained in this email is strictly confidential and for > the use of the addressee only, unless otherwise indicated. If you are not > the intended recipient, please do not read, copy, use or disclose to others > this message or any attachment. Please also notify the sender by replying > to this email or by telephone (+44(020 7896 0011) and then delete the email > and any copies of it. Opinions, conclusion (etc) that do not relate to the > official business of this company shall be understood as neither given nor > endorsed by it. IG is a trading name of IG Markets Limited (a company > registered in England and Wales, company number 04008957) and IG Index > Limited (a company registered in England and Wales, company number > 01190902). Registered address at Cannon Bridge House, 25 Dowgate Hill, > London EC4R 2YA. Both IG Markets Limited (register number 195355) and IG > Index Limited (register number 114059) are authorised and regulated by the > Financial Conduct Authority. >
