Thanks Sushant and Enrico! This is a really good point. According to the 3.6 documentation, the feature is disabled by default. https://zookeeper.apache.org/doc/r3.6.2/zookeeperAdmin.html#ch_administration. However, checking the code, the default is enabled.
Let me set the zookeeper.digest.enabled to false and see how the write operation performs. Best, Li On Fri, Feb 19, 2021 at 1:32 PM Sushant Mane <sushantma...@gmail.com> wrote: > Hi Li, > > On 3.6.2 consistency checker (adhash based) is enabled by default: > > https://github.com/apache/zookeeper/blob/803c7f1a12f85978cb049af5e4ef23bd8b688715/zookeeper-server/src/main/java/org/apache/zookeeper/server/ZooKeeperServer.java#L136 > . > It is not present in ZK 3.4.14. > > This feature does have some impact on write performance. > > Thanks, > Sushant > > > On Fri, Feb 19, 2021 at 12:50 PM Enrico Olivelli <eolive...@gmail.com> > wrote: > > > Li, > > I wonder of we have some new throttling/back pressure mechanisms that is > > enabled by default. > > > > Does anyone has some pointer to relevant implementations? > > > > > > Enrico > > > > Il Ven 19 Feb 2021, 19:46 Li Wang <li4w...@gmail.com> ha scritto: > > > > > Hi, > > > > > > We switched to Netty on both client side and server side and the > > > performance issue is still there. Anyone has any insights on what > could > > be > > > the cause of higher latency? > > > > > > Thanks, > > > > > > Li > > > > > > > > > > > > On Mon, Feb 15, 2021 at 2:17 PM Li Wang <li4w...@gmail.com> wrote: > > > > > > > Hi Enrico, > > > > > > > > > > > > Thanks for the reply. > > > > > > > > > > > > 1. We are using NIO based stack, not Netty based yet. > > > > > > > > 2. Yes, here are some metrics on the client side. > > > > > > > > > > > > 3.6: throughput: 7K, failure: 81215228, Avg Latency: 57ms, Max > Latency > > > 31s > > > > > > > > 3.4: throughput: 15k, failure: 0, Avg Latency: 30ms, Max Latency: > > 1.6s > > > > > > > > > > > > 3. Yes, the JVM and zoo.cfg config are the exact same > > > > > > > > 10G of Heap > > > > > > > > 13G of Memory > > > > > > > > 5 Participante > > > > > > > > 5 Observere > > > > > > > > Client session timeout: 3000ms > > > > > > > > Server min session time: 4000ms > > > > > > > > > > > > > > > > 4. Yes, there are two types of WARN logs and many “Expiring session” > > > > INFO log > > > > > > > > > > > > 2021-02-15 22:04:36,506 [myid:4] - WARN > > > > [NIOWorkerThread-7:NIOServerCnxn@365] - Unexpected exception > > > > > > > > EndOfStreamException: Unable to read additional data from client, it > > > > probably closed the socket: address = /100.108.63.116:43366, > session = > > > > 0x400189fee9a000b > > > > > > > > at > > > > > > > > > > org.apache.zookeeper.server.NIOServerCnxn.handleFailedRead(NIOServerCnxn.java:164) > > > > > > > > at > > org.apache.zookeeper.server.NIOServerCnxn.doIO(NIOServerCnxn.java:327) > > > > > > > > at > > > > > > > > > > org.apache.zookeeper.server.NIOServerCnxnFactory$IOWorkRequest.doWork(NIOServerCnxnFactory.java:522) > > > > > > > > at > > > > > > > > > > org.apache.zookeeper.server.WorkerService$ScheduledWorkRequest.run(WorkerService.java:154) > > > > > > > > at > > > > > > > > > > java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) > > > > > > > > at > > > > > > > > > > java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) > > > > > > > > at java.base/java.lang.Thread.run(Thread.java:834) > > > > > > > > > > > > 2021-02-15 22:05:14,428 [myid:4] - WARN > > > > [SyncThread:4:SyncRequestProcessor@188] - Too busy to snap, skipping > > > > > > > > > > > > 2021-02-15 22:01:51,427 [myid:4] - INFO > > > > [SessionTracker:ZooKeeperServer@610] - Expiring session > > > > 0x400189fee9a001e, timeout of 4000ms exceeded > > > > > > > > > > > > > > > > 5. Yes we upgrade both the client and the server to 3.6. Actually, > the > > > > issue happened with the combinations of > > > > > > > > > > > > 3.4 client and 3.6 server > > > > > > > > 3.6 client and 3.6 server > > > > > > > > Please let me know if you need any additional info. > > > > > > > > Thanks, > > > > > > > > Li > > > > > > > > > > > > > > > > > > > > On Mon, Feb 15, 2021 at 1:44 PM Li Wang <li4w...@gmail.com> wrote: > > > > > > > >> Hi Enrico, > > > >> > > > >> Thanks for the reply. > > > >> > > > >> 1. We are using direct NIO based stack, not Netty based yet. > > > >> 2. Yes, on the client side, here are the metrics > > > >> > > > >> 3.6: > > > >> > > > >> > > > >> > > > >> > > > >> On Mon, Feb 15, 2021 at 10:44 AM Enrico Olivelli < > eolive...@gmail.com > > > > > > >> wrote: > > > >> > > > >>> IIRC The main difference is about the switch to Netty 4 and about > > using > > > >>> more DirectMemory. Are you using the Netty based stack? > > > >>> > > > >>> Apart from that macro difference there have been many many changes > > > since > > > >>> 3.4. > > > >>> > > > >>> Do you have some metrics to share? > > > >>> Are the JVM configurations and zoo.cfg configuration equals to > each > > > >>> other? > > > >>> > > > >>> Do you see warnings on the server logs? > > > >>> > > > >>> Did you upgrade both the client and the server or only the server? > > > >>> > > > >>> Enrico > > > >>> > > > >>> > > > >>> Il Lun 15 Feb 2021, 18:30 Li Wang <li4w...@gmail.com> ha scritto: > > > >>> > > > >>> > Hi, > > > >>> > > > > >>> > We want to upgrade from 3.4.14 to 3.6.2. During the perform/load > > > >>> > comparison test, it was found that the performance of 3.6 has > been > > > >>> > significantly degraded compared to 3.4 for the write operation. > > Under > > > >>> the > > > >>> > same load, there was a huge number of SessionExpired and > > > ConnectionLoss > > > >>> > errors in 3.6 while no such errors in 3.4. > > > >>> > > > > >>> > The load testing is 500 concurrent users with a cluster of 5 > > > >>> participants > > > >>> > and 5 observers. The min session timeout on the server side is > > > 4000ms. > > > >>> > > > > >>> > I wonder if anyone has seen the same issue and has any insights > on > > > what > > > >>> > could be the cause of the performance degradation. > > > >>> > > > > >>> > Thanks > > > >>> > > > > >>> > Li > > > >>> > > > > >>> > > > >> > > > > > >
