Well, we've solved the problem when there is only one transaction id per job. The operators can fetch the transaction ids from the JobEventListenerFactory (you can find this in master now). The issue is, when we are trying to combine multiple job specs into one feed job, the operators at runtime don't have a memory of which "job spec" they originally belonged to which could tell them which one of the transaction ids that they should use.
Steven On Fri, Nov 17, 2017 at 11:25 AM, abdullah alamoudi <[email protected]> wrote: > > I think that this works and seems like the question is how different > operators in the job can get their transaction ids. > > ~Abdullah. > > > On Nov 17, 2017, at 11:21 AM, Steven Jacobs <[email protected]> wrote: > > > > From the conversation, it seems like nobody has the full picture to > propose > > the design? > > For deployed jobs, the idea is to use the same job specification but > create > > a new Hyracks job and Asterix Transaction for each execution. > > > > Steven > > > > On Fri, Nov 17, 2017 at 11:10 AM, abdullah alamoudi <[email protected]> > > wrote: > > > >> I can e-meet anytime (moved to Sunnyvale). We can also look at a > proposed > >> design and see if it can work > >> Back to my question, how were you planning to change the transaction id > if > >> we forget about the case with multiple datasets (feed job)? > >> > >> > >>> On Nov 17, 2017, at 10:38 AM, Steven Jacobs <[email protected]> wrote: > >>> > >>> Maybe it would be good to have a meeting about this with all interested > >>> parties? > >>> > >>> I can be on-campus at UCI on Tuesday if that would be a good day to > meet. > >>> > >>> Steven > >>> > >>> On Fri, Nov 17, 2017 at 9:36 AM, abdullah alamoudi <[email protected] > > > >>> wrote: > >>> > >>>> Also, was wondering how would you do the same for a single dataset > >>>> (non-feed). How would you get the transaction id and change it when > you > >>>> re-run? > >>>> > >>>> On Nov 17, 2017 7:12 AM, "Murtadha Hubail" <[email protected]> > wrote: > >>>> > >>>>> For atomic transactions, the change was merged yesterday. For entity > >>>> level > >>>>> transactions, it should be a very small change. > >>>>> > >>>>> Cheers, > >>>>> Murtadha > >>>>> > >>>>>> On Nov 17, 2017, at 6:07 PM, abdullah alamoudi <[email protected]> > >>>>> wrote: > >>>>>> > >>>>>> I understand that is not the case right now but what you're working > >> on? > >>>>>> > >>>>>> Cheers, > >>>>>> Abdullah. > >>>>>> > >>>>>> > >>>>>>> On Nov 17, 2017, at 7:04 AM, Murtadha Hubail <[email protected]> > >>>>> wrote: > >>>>>>> > >>>>>>> A transaction context can register multiple primary indexes. > >>>>>>> Since each entity commit log contains the dataset id, you can > >>>> decrement > >>>>> the active operations on > >>>>>>> the operation tracker associated with that dataset id. > >>>>>>> > >>>>>>> On 17/11/2017, 5:52 PM, "abdullah alamoudi" <[email protected]> > >>>> wrote: > >>>>>>> > >>>>>>> Can you illustrate how a deadlock can happen? I am anxious to know. > >>>>>>> Moreover, the reason for the multiple transaction ids in feeds is > >>>> not > >>>>> simply because we compile them differently. > >>>>>>> > >>>>>>> How would a commit operator know which dataset active operation > >>>>> counter to decrement if they share the same id for example? > >>>>>>> > >>>>>>>> On Nov 16, 2017, at 9:46 PM, Xikui Wang <[email protected]> wrote: > >>>>>>>> > >>>>>>>> Yes. That deadlock could happen. Currently, we have one-to-one > >>>>> mappings for > >>>>>>>> the jobs and transactions, except for the feeds. > >>>>>>>> > >>>>>>>> @Abdullah, after some digging into the code, I think probably we > can > >>>>> use a > >>>>>>>> single transaction id for the job which feeds multiple datasets? > See > >>>>> if I > >>>>>>>> can convince you. :) > >>>>>>>> > >>>>>>>> The reason we have multiple transaction ids in feeds is that we > >>>> compile > >>>>>>>> each connection job separately and combine them into a single feed > >>>>> job. A > >>>>>>>> new transaction id is created and assigned to each connection job, > >>>>> thus for > >>>>>>>> the combined job, we have to handle the different transactions as > >>>> they > >>>>>>>> are embedded in the connection job specifications. But, what if we > >>>>> create a > >>>>>>>> single transaction id for the combined job? That transaction id > will > >>>> be > >>>>>>>> embedded into each connection so they can write logs freely, but > the > >>>>>>>> transaction will be started and committed only once as there is > only > >>>>> one > >>>>>>>> feed job. In this way, we won't need > multiTransactionJobletEventLis > >>>>> tener > >>>>>>>> and the transaction id can be removed from the job specification > >>>>> easily as > >>>>>>>> well (for Steven's change). > >>>>>>>> > >>>>>>>> Best, > >>>>>>>> Xikui > >>>>>>>> > >>>>>>>> > >>>>>>>>> On Thu, Nov 16, 2017 at 4:26 PM, Mike Carey <[email protected]> > >>>>> wrote: > >>>>>>>>> > >>>>>>>>> I worry about deadlocks. The waits for graph may not understand > >>>> that > >>>>>>>>> making t1 wait will also make t2 wait since they may share a > thread > >>>> - > >>>>>>>>> right? Or do we have jobs and transactions separately > represented > >>>>> there > >>>>>>>>> now? > >>>>>>>>> > >>>>>>>>>> On Nov 16, 2017 3:10 PM, "abdullah alamoudi" < > [email protected]> > >>>>> wrote: > >>>>>>>>>> > >>>>>>>>>> We are using multiple transactions in a single job in case of > feed > >>>>> and I > >>>>>>>>>> think that this is the correct way. > >>>>>>>>>> Having a single job for a feed that feeds into multiple datasets > >>>> is a > >>>>>>>>> good > >>>>>>>>>> thing since job resources/feed resources are consolidated. > >>>>>>>>>> > >>>>>>>>>> Here are some points: > >>>>>>>>>> - We can't use the same transaction id to feed multiple > datasets. > >>>> The > >>>>>>>>> only > >>>>>>>>>> other option is to have multiple jobs each feeding a different > >>>>> dataset. > >>>>>>>>>> - Having multiple jobs (in addition to the extra resources used, > >>>>> memory > >>>>>>>>>> and CPU) would then forces us to either read data from external > >>>>> sources > >>>>>>>>>> multiple times, parse records multiple times, etc > >>>>>>>>>> or having to have a synchronization between the different jobs > and > >>>>> the > >>>>>>>>>> feed source within asterixdb. IMO, this is far more complicated > >>>> than > >>>>>>>>> having > >>>>>>>>>> multiple transactions within a single job and the cost far > >> outweigh > >>>>> the > >>>>>>>>>> benefits. > >>>>>>>>>> > >>>>>>>>>> P.S, > >>>>>>>>>> We are also using this for bucket connections in Couchbase > >>>> Analytics. > >>>>>>>>>> > >>>>>>>>>>> On Nov 16, 2017, at 2:57 PM, Till Westmann <[email protected]> > >>>>> wrote: > >>>>>>>>>>> > >>>>>>>>>>> If there are a number of issue with supporting multiple > >>>> transaction > >>>>> ids > >>>>>>>>>>> and no clear benefits/use-cases, I’d vote for simplification :) > >>>>>>>>>>> Also, code that’s not being used has a tendency to "rot" and > so I > >>>>> think > >>>>>>>>>>> that it’s usefulness might be limited by the time we’d find a > use > >>>>> for > >>>>>>>>>>> this functionality. > >>>>>>>>>>> > >>>>>>>>>>> My 2c, > >>>>>>>>>>> Till > >>>>>>>>>>> > >>>>>>>>>>>> On 16 Nov 2017, at 13:57, Xikui Wang wrote: > >>>>>>>>>>>> > >>>>>>>>>>>> I'm separating the connections into different jobs in some of > my > >>>>>>>>>>>> experiments... but that was intended to be used for the > >>>>> experimental > >>>>>>>>>>>> settings (i.e., not for master now)... > >>>>>>>>>>>> > >>>>>>>>>>>> I think the interesting question here is whether we want to > >> allow > >>>>> one > >>>>>>>>>>>> Hyracks job to carry multiple transactions. I personally think > >>>> that > >>>>>>>>>> should > >>>>>>>>>>>> be allowed as the transaction and job are two separate > concepts, > >>>>> but I > >>>>>>>>>>>> couldn't find such use cases other than the feeds. Does anyone > >>>>> have a > >>>>>>>>>> good > >>>>>>>>>>>> example on this? > >>>>>>>>>>>> > >>>>>>>>>>>> Another question is, if we do allow multiple transactions in a > >>>>> single > >>>>>>>>>>>> Hyracks job, how do we enable commit runtime to obtain the > >>>> correct > >>>>> TXN > >>>>>>>>>> id > >>>>>>>>>>>> without having that embedded as part of the job specification. > >>>>>>>>>>>> > >>>>>>>>>>>> Best, > >>>>>>>>>>>> Xikui > >>>>>>>>>>>> > >>>>>>>>>>>> On Thu, Nov 16, 2017 at 1:01 PM, abdullah alamoudi < > >>>>>>>>> [email protected]> > >>>>>>>>>>>> wrote: > >>>>>>>>>>>> > >>>>>>>>>>>>> I am curious as to how feed will work without this? > >>>>>>>>>>>>> > >>>>>>>>>>>>> ~Abdullah. > >>>>>>>>>>>>>> On Nov 16, 2017, at 12:43 PM, Steven Jacobs < > [email protected] > >>> > >>>>>>>>> wrote: > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> Hi all, > >>>>>>>>>>>>>> We currently have MultiTransactionJobletEventLis > tenerFactory, > >>>>> which > >>>>>>>>>>>>> allows > >>>>>>>>>>>>>> for one Hyracks job to run multiple Asterix transactions > >>>>> together. > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> This class is only used by feeds, and feeds are in process > of > >>>>>>>>>> changing to > >>>>>>>>>>>>>> no longer need this feature. As part of the work in > >>>> pre-deploying > >>>>>>>>> job > >>>>>>>>>>>>>> specifications to be used by multiple hyracks jobs, I've > been > >>>>>>>>> working > >>>>>>>>>> on > >>>>>>>>>>>>>> removing the transaction id from the job specifications, as > we > >>>>> use a > >>>>>>>>>> new > >>>>>>>>>>>>>> transaction for each invocation of a deployed job. > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> There is currently no clear way to remove the transaction id > >>>> from > >>>>>>>>> the > >>>>>>>>>> job > >>>>>>>>>>>>>> spec and keep the option for MultiTransactionJobletEventLis > >>>>>>>>>> tenerFactory. > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> The question for the group is, do we see a need to maintain > >>>> this > >>>>>>>>> class > >>>>>>>>>>>>> that > >>>>>>>>>>>>>> will no longer be used by any current code? Or, an other > >> words, > >>>>> is > >>>>>>>>>> there > >>>>>>>>>>>>> a > >>>>>>>>>>>>>> strong possibility that in the future we will want multiple > >>>>>>>>>> transactions > >>>>>>>>>>>>> to > >>>>>>>>>>>>>> share a single Hyracks job, meaning that it is worth > figuring > >>>> out > >>>>>>>>> how > >>>>>>>>>> to > >>>>>>>>>>>>>> maintain this class? > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> Steven > >>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>> > >>>>> > >>>> > >> > >> > >
