We could use the async writer to store the events to the database when using the redis. Redis cluster has the persistent storage at the same time.
Willem Jiang Twitter: willemjiang Weibo: 姜宁willem On Mon, Aug 20, 2018 at 11:08 AM, bismy <bi...@qq.com> wrote: > One doubt about redis, maybe not correct. > > > For transactions persistence is very important, if we use redis, the > transactions may lose persistence property. Event you provide retry > mechanism, but how about the redis instance is restarted and memory data > get lost? > > > Do you mean that using redis clusters and sync memory data between > clusters and assume that clusters is high available? > > > ------------------ 原始邮件 ------------------ > 发件人: "willem.jiang"<willem.ji...@gmail.com>; > 发送时间: 2018年8月16日(星期四) 中午11:00 > 收件人: "dev"<dev@servicecomb.apache.org>; > > 主题: Re: Performance tuning of ServiceComb Saga Pack > > > > We cannot guarantee to update the redis and DB at the same time, we can > just do the retry in our code. > > > > Willem Jiang > > Twitter: willemjiang > Weibo: 姜宁willem > > On Thu, Aug 16, 2018 at 10:29 AM, fu chengeng <oliug...@hotmail.com> > wrote: > > > Hi Willem > > why not just store 'finished transacation' data to db in a async way.can > > we guarantee update on both > > db and redis are success at same time when the transation is aborted? > > 发件人: Willem Jiang > > 发送时间: 8月16日星期四 09:40 > > 主题: Re: Performance tuning of ServiceComb Saga Pack > > 收件人: dev@servicecomb.apache.org > > > > > > 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 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 : > > > > > > 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 > > > > > > > >
