Hi Enrico, Sushant, I re-run the perf test with the data consistency check feature disabled (i.e. -Dzookeeper.digest.enabled=false), the write performance issue of 3.6 is still there.
With everything exactly the same, the throughput of 3.6 was only 1/2 of 3.4 and the max latency was more than 8 times. Any other points or thoughts? Cheers, Li On Sat, Feb 20, 2021 at 9:04 PM Li Wang <li4w...@gmail.com> wrote: > 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 >> > > >>> > >> > > >>> >> > > >> >> > > >> > >> >
