Re: [infinispan-dev] [hibernate-dev] Infinispan tx, config and multithreading

I am not an expert on this part of Lucene, but it looks like to me that the IndexWriter is the "driver/coordinator", and it's decisions are affected by a pluggable MergeScheduler; they do stuff on the internal buffers of the IndexWriter (dequeue the pending segments to be written to the index), but it shouldn't matter what they exactly do as the internal status of these classes are unaffected by our transactions. They take some decision about writing segments to the Directory and committing changes ("sync()") : as you implement this Directory you should only have to take care of this class, I don't think the MergeScheduler(s) are relevant: it just happens that the thread going to apply changes to the index might be a different one than the one pushing changes to the IndexWriter. In the Directory implementation you should use transactions to push state changes to the "underlying storage": as FSDirectory is playing with file descriptors and flushes, you do the same with Infinispan transactions. 2009/8/14 Łukasz Moreń <lukasz.moren(a)gmail.com&gt;: > Yes, right, MergeSchedulers. > > 2009/8/14 Sanne Grinovero <sanne.grinovero(a)gmail.com&gt; >> >> what are these "other" threads? Are you speaking about the >> MergeSchedulers? >> >> 2009/8/13 Łukasz Moreń <lukasz.moren(a)gmail.com&gt;: >>> IndexWriter processes index update and delegates some job to other >>> threads and waits when they finish. These "other" threads works on >>> data modified >>> in IndexWriter transaction. So I think if I use transaction per >>> thread, "others" would not see data modified by IndexWriter until >>> commit. >>> >>> 2009/8/13, Emmanuel Bernard <emmanuel(a)hibernate.org&gt;: >>>> Ah I thought it was using multiple threads because of your mass >>>> indexing. I did not know some threads were span specifically for >>>> the >>>> Infinispan directory. >>>> >>>> On 13 août 09, at 17:34, Sanne Grinovero wrote: >>>> >>>>> Hi Łukasz, >>>>> what is your usage of these threads? did you consider using one >>>>> transaction per thread? >>>>> >>>>> Sanne >>>>> >>>>> 2009/8/13 Łukasz Moreń <lukasz.moren(a)gmail.com&gt;: >>>>>> Newly created threads were not associated with any >>>>>> transaction, so I >>>>>> suppose it was a problem. Sharing transaction between threads >>>>>> seems >>>>>> to >>>>>> be a good solution. >>>>>> Thanks for help! >>>>>> >>>>>> 2009/8/13, Jason T. Greene <jason.greene(a)redhat.com&gt;: >>>>>>> Correct. Also there could be read races as well, so if you are >>>>>>> going to >>>>>>> share a tx between threads, i would use some shared lock to >>>>>>> gaurantee >>>>>>> that only one thread can use it at a time. BTW this means you >>>>>>> have >>>>>>> to >>>>>>> properly suspend/resume the TX via the TM API as well. >>>>>>> >>>>>>> Emmanuel Bernard wrote: >>>>>>>> Modifying a transaction means applying muations (like SQL >>>>>>>> INSERT / >>>>>>>> UPDATE / DELETE) to the transactional resource? >>>>>>>> >>>>>>>> On 13 août 09, at 15:07, Jason T. Greene wrote: >>>>>>>> >>>>>>>>> When using transactions, the context is bound to the >>>>>>>>> transaction, and >>>>>>>>> you can move a transaction between threads. However, you >>>>>>>>> should >>>>>>>>> only >>>>>>>>> be modifying a transaction with one thread at a time. >>>>>>>>> >>>>>>>>> Emmanuel Bernard wrote: >>>>>>>>>> Could it be that you are not using the same transaction >>>>>>>>>> between >>>>>>>>>> different threads (ie you physically start different ones or >>>>>>>>>> different "Infinispan contexts")? >>>>>>>>>> Infini guys, do you support transactional operation spanning >>>>>>>>>> several >>>>>>>>>> concurrent threads? >>>>>>>>>> On 13 août 09, at 14:04, Łukasz Moreń wrote: >>>>>>>>>>> I've tried with JBoss AS transaction manager and >>>>>>>>>>> JBossStandaloneTM. >>>>>>>>>>> The result is this same in all cases - error during merge. >>>>>>>>>>> >>>>>>>>>>> 2009/8/12, Emmanuel Bernard <emmanuel(a)hibernate.org&gt;: >>>>>>>>>>>> Ok I understand better now. >>>>>>>>>>>> Do your tests in JBoss AS with it's decent transaction >>>>>>>>>>>> manager >>>>>>>>>>>> (infinispan should have a config for it) >>>>>>>>>>>> For unit testing, force the indexing process in >>>>>>>>>>>> hibernate to >>>>>>>>>>>> use a >>>>>>>>>>>> single thread (I ghnk it's possible ask Sanne of you don't >>>>>>>>>>>> know how). >>>>>>>>>>>> >>>>>>>>>>>> Exposing some configuration to infinispan makes sense. >>>>>>>>>>>> can you >>>>>>>>>>>> start a >>>>>>>>>>>> thread explainig what is configurable and which one you >>>>>>>>>>>> think >>>>>>>>>>>> we >>>>>>>>>>>> should expose to hsearch users. Ideally I would like to >>>>>>>>>>>> offer >>>>>>>>>>>> one or >>>>>>>>>>>> two defaut config scenarios and allow to fallback to a >>>>>>>>>>>> custom >>>>>>>>>>>> config. >>>>>>>>>>>> >>>>>>>>>>>> Emmanuel >>>>>>>>>>>> >>>>>>>>>>>> On 12 août 2009, at 11:58, Łukasz Moreń >>>>>>>>>>>> <lukasz.moren(a)gmail.com&gt; >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> Sorry, but my wifi does not work well today. I will try >>>>>>>>>>>>> to >>>>>>>>>>>>> explain >>>>>>>>>>>>> it more clear. >>>>>>>>>>>>> >>>>>>>>>>>>> I'm using DummyTransactionManager available for >>>>>>>>>>>>> Infinispan. >>>>>>>>>>>>> It associates transaction with the calling thread. >>>>>>>>>>>>> >>>>>>>>>>>>> Steps to update index: >>>>>>>>>>>>> >>>>>>>>>>>>> 1. index writer acquires lock - begin of transaction >>>>>>>>>>>>> >>>>>>>>>>>>> 2. if it is necessary, index writer delegates new >>>>>>>>>>>>> threads to >>>>>>>>>>>>> do >>>>>>>>>>>>> merge work. >>>>>>>>>>>>> Those merge threads do not see changes made so far from >>>>>>>>>>>>> begin of >>>>>>>>>>>>> transaction, >>>>>>>>>>>>> and are looking for segments which are not yet in index. >>>>>>>>>>>>> Changes will be visible when AD.3 is completed. >>>>>>>>>>>>> For tests i tried to commit transaction when merge starts >>>>>>>>>>>>> and then >>>>>>>>>>>>> everything worked well. But then i need to start it >>>>>>>>>>>>> again. >>>>>>>>>>>>> >>>>>>>>>>>>> 3. index writer releases lock - transaction is >>>>>>>>>>>>> commited, all >>>>>>>>>>>>> changes >>>>>>>>>>>>> made in this transaction are visible for other threads. >>>>>>>>>>>>> >>>>>>>>>>>>> Maybe using some other transaction manager could help? >>>>>>>>>>>>> >>>>>>>>>>>>> What about Infinispan cache configuration? Some >>>>>>>>>>>>> configuration >>>>>>>>>>>>> mechanism should be exposed to the user, >>>>>>>>>>>>> or we can hardcoded one in InfinispanDirectoryProvider is >>>>>>>>>>>>> enough? >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> 2009/8/12 Emmanuel Bernard <emmanuel(a)hibernate.org&gt; >>>>>>>>>>>>> why? >>>>>>>>>>>>> Emmanuel Bernard >>>>>>>>>>>>> Pending >>>>>>>>>>>>> you there? >>>>>>>>>>>>> Emmanuel Bernard >>>>>>>>>>>>> Pending >>>>>>>>>>>>> Ok please describe in details what is going on. From what >>>>>>>>>>>>> you are >>>>>>>>>>>>> describing the tx cannot see all segments which looks >>>>>>>>>>>>> like an >>>>>>>>>>>>> infinispan bug to me. >>>>>>>>>>>>> Pending >>>>>>>>>>>>> >>>>>>>>>>>>> As a back up you can try wo transaction and see if that >>>>>>>>>>>>> works >>>>>>>>>>>>> Emmanuel Bernard >>>>>>>>>>>>> Pending >>>>>>>>>>>>> technically the lucene index should cope with that >>>>>>>>>>>>> Emmanuel Bernard >>>>>>>>>>>>> 11:16 >>>>>>>>>>>>> but I like this approach less >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> Let's try and chat by email IF I'm not online, I need >>>>>>>>>>>>> to run >>>>>>>>>>>>> on some >>>>>>>>>>>>> errands today. >>>>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> infinispan-dev mailing list >>>>>>>>>> infinispan-dev(a)lists.jboss.org >>>>>>>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Jason T. Greene >>>>>>>>> JBoss, a division of Red Hat >>>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Jason T. Greene >>>>>>> JBoss, a division of Red Hat >>>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> infinispan-dev mailing list >>>>>> infinispan-dev(a)lists.jboss.org >>>>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev >>>>> >>>>> _______________________________________________ >>>>> hibernate-dev mailing list >>>>> hibernate-dev(a)lists.jboss.org >>>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev >>>> >>>> >>> > >