Hi Dexin, ``` 1. Does the transactional messaging need to be "exactly only once" delivered? ```
Please check out https://issues.apache.org/jira/browse/ROCKETMQ-124 ``` 2. Where to store the transaction state? Since the state must be persistent and also updated. ``` We could reuse the rocketmq-store model to store the transaction state. And, don't worry about the dirty pages if you follow the rule: Append Only. Regards, yukon On Wed, Mar 7, 2018 at 12:11 PM, 李 德鑫 <[email protected]> wrote: > Thank you, Yukon! > > > I still have some question about transactional messaging > > 1. Does the transactional messaging need to be "exactly only once" > delivered? > 2. Where to store the transaction state? Since the state must be > persistent and also updated. > > > About the second question, I've considered about some methods > > 1. Inside of the message. But it is said that this would generate lots > of dirty pages on the OS. > 2. In a database, especially an SQL database. Since class > JDBCTransactionStore already exists. But I want to know whether the DB will > be the bottleneck of performance or scalability. > 3. Like Kafka, use an internal topic called Transaction log. It will > record all the operation about transaction states. And store the latest > states in the memory. If a partition crashed, It will read the log to > recover. But the recovery would be slow. > 4. Similar to 3, store and the transaction state in the Transaction > log. But if there's a lot of transaction message, (I guess)this would be > like 1 to generate many dirty pages. > > > Regards, > Dexin > ________________________________ > 发件人: yukon <[email protected]> > 发送时间: 2018年3月5日 12:28:47 > 收件人: dev > 主题: Re: 答复: [GSOC|ROCKETMQ-123]Support Distributed Transactional Messaging > > Hi, > > The links you mentioned just are interfaces, we should implement these > APIs. > > Regards, > yukon > > On Tue, Feb 27, 2018 at 12:07 PM, 李 德鑫 <[email protected]> wrote: > > > My previous email didn't clarify the question clearly, so I'll try to > make > > it in detail. > > > > > > In this jira's(https://issues.apache.org/jira/browse/ROCKETMQ-123) > > description: > > > > > > > > > > Implement a TransactionProducer and LocalTransactionChecker, guarantee > > message delivery and local transaction operations are atomic. > > > > The following is the simple transactional messaging flow: > > > > 1. TransactionProducer sends a half message to the broker. A half message > > means it's not confirmed and can't be delivered to the consumer. > > > > 2. TransactionProducer executes the specific local transaction. > > > > 3. Commit or Rollback the half message according to the status of the > > local transaction. A half message will be deleted if it's rollbacked and > > delivered to the consumer if it's committed. > > > > > > > > The 1st step I found in https://github.com/apache/ > > rocketmq/blob/master/client/src/main/java/org/apache/ > > rocketmq/client/impl/producer/DefaultMQProducerImpl.java#L964 > > > > The 2nd step I found in https://github.com/apache/ > > rocketmq/blob/master/client/src/main/java/org/apache/ > > rocketmq/client/impl/producer/DefaultMQProducerImpl.java#L977 > > > > The 3rd step I found in https://github.com/apache/ > > rocketmq/blob/master/client/src/main/java/org/apache/ > > rocketmq/client/impl/producer/DefaultMQProducerImpl.java#L1026 for > client > > and https://github.com/apache/rocketmq/blob/master/broker/ > > src/main/java/org/apache/rocketmq/broker/processor/ > > EndTransactionProcessor.java#L49 for broker > > > > > > And my question is what is the part to be implemented for this issue? Is > > there anything I missed? > > > > > > > > ________________________________ > > 发件人: 李 德鑫 <[email protected]> > > 发送时间: 2018年2月23日 9:35:17 > > 收件人: [email protected] > > 主题: [GSOC|ROCKETMQ-123]Support Distributed Transactional Messaging > > > > Hi, > > > > I am working on this issue > > (https://issues.apache.org/jira/browse/ROCKETMQ-123) as my GSOC project > > [ROCKETMQ-123] Support Distributed Transactional Messaging ...< > > https://issues.apache.org/jira/browse/ROCKETMQ-123> > > In most businesses, transactional messaging is frequently used to make a > > series of operations as an atomic transaction. At present, RocketMQ > doesn't > > support ... > > issues.apache.org > > > > > > > > However, there already have > > TransactionMQProducer > > > > https://github.com/apache/rocketmq/blob/master/client/ > > src/main/java/org/apache/rocketmq/client/producer/ > > TransactionMQProducer.java<https://github.com/apache/ > > rocketmq/blob/master/client/src/main/java/org/apache/ > > rocketmq/client/producer/TransactionMQProducer.java#L23> > > [https://avatars3.githubusercontent.com/u/47359?s=400&v=4]< > > https://github.com/apache/rocketmq/blob/master/client/src/main/java/org/ > > apache/rocketmq/client/producer/TransactionMQProducer.java#L23> > > > > apache/rocketmq<https://github.com/apache/rocketmq/ > > blob/master/client/src/main/java/org/apache/rocketmq/client/producer/ > > TransactionMQProducer.java#L23> > > rocketmq - Mirror of Apache RocketMQ > > github.com > > > > and TransactionCheckListener > > https://github.com/apache/rocketmq/blob/master/client/ > > src/main/java/org/apache/rocketmq/client/producer/ > > TransactionCheckListener.java > > > > So, what is the part I should implement for this issue? > > > > Regards, > > Dexin Li > > > > >
