Here is an abstracted design of how redis works: https://raw.githubusercontent.com/crystaldust/saga-performance-optimization/master/saga-redis.jpg
Willem Jiang <willem.ji...@gmail.com> 于2018年8月16日周四 上午9:40写道： > Hi Amos > > Alpha send response to the Omega once the message is updated into redis, > then we just store the transaction events into the database in async way > (we don't change the states here). > Current Redis cluster provides the persistent storage, it could reduce lot > of effort of us. > Now we just use redis as a smaller table for tracking all the unfinished > transaction status to get better performance. > If the transaction is aborted, we can updated the transaction in the DB and > Redis at same time, if any of those calls is failed, I think we just keep > trying to update the status. > > > > > Willem Jiang > > Twitter: willemjiang > Weibo: 姜宁willem > > On Wed, Aug 15, 2018 at 10:48 PM, Zheng Feng <zh.f...@gmail.com> wrote: > > > Hi Willem, > > > > It makes sense to use the redis to store the pending transactions (I > assume > > that you mean these are the "HOT" ones). But we could be very careful to > > "write" the transaction status, and it should be stored in the database > at > > last. So I think we must make sure the transaction status in the redis > and > > the DB is consist and we SHOULD NOT lose the any status of the > transaction. > > > > How will you use the redis and the database when storing the status of > > transaction ? > > 1. write to the redis and the redis will sync to the database later. if > > failed, rollback the transaction. > > 2. both write to the redis and the database. if any of them failed, > > rollback the transaction. > > > > We need the more detail :) > > > > Amos > > > > 2018-08-15 8:48 GMT+08:00 Willem Jiang <willem.ji...@gmail.com>: > > > > > Hi, > > > > > > With the help of JuZheng[1][2], we managed to deploy the > saga-spring-demo > > > into K8s and start the Jmeter tests for it. By running the test for a > > > while, the DB CPU usage is very high and the response time is up 2~3 > > > seconds per call. > > > > > > It looks like all the event are stored into the database in the same > > table > > > and never cleaned. > > > Now we are thinking use redis to store the hot data (the saga > transaction > > > which is not closed), and put the cold data (which is used for > auditing) > > > into database. In this way it could keep the event data smaller and > the > > > event sanner[4] can just go through the unfinished the Saga > transactions > > to > > > fire the timeout event or the compensation event. > > > > > > Any thought? > > > > > > [1]https://github.com/apache/incubator-servicecomb-saga/pull/250 > > > [2]https://github.com/apache/incubator-servicecomb-saga/pull/252 > > > [3] > > > https://github.com/apache/incubator-servicecomb-saga/ > > > tree/master/saga-demo/saga-spring-demo > > > [4] > > > https://github.com/apache/incubator-servicecomb-saga/blob/ > > > 44491f1dcbb9353792cb44d0be60946e0e4d7a1a/alpha/alpha-core/ > > > src/main/java/org/apache/servicecomb/saga/alpha/core/EventScanner.java > > > > > > Willem Jiang > > > > > > Twitter: willemjiang > > > Weibo: 姜宁willem > > > > > >
