Interesting, thanks for sharing the results!
It will be hard to figure out what changed since the 3.4.6 release. Many
new features added. Still, it would be good to find out which version /
commit was responsible for the most performance degradation.
You wrote before:
> A while back I performed similar comparisons of 3.4.6 vs 3.6.x and I got
> slow results in 3.6.x initially, but disabling digest.enabled fixed it and
> the two versions were then comparable. In 3.8.0 I am seeing poor results
> with or without digest enabled.
Then later:
> 27,052: 3.4.6
> 15,993:3.6.3
> 15,943:3.7.1
> 16,805: 3.8.0, digest.enabled=true:
> 16,682: 3.8.0: digest.enabled=false
> *16,370: 3.8.0 NullMetricsProvider*
Was the "15,993:3.6.3" measured with or without digest? It sounds like
earlier you were able to get good results with 3.6.x
(using digest.enabled=false). Is this still reproducible with 3.6.3? If
yes, then still I would look around the digest feature for potential root
cause.
On the other hand, the digest feature should not really affect the read
path, as far as I understood. But I also don't know how the benchmarking
tool executes the operations (maybe there are writes running parallel with
reads?).
Máté
On Mon, Aug 29, 2022 at 7:00 AM Will Now <wnowicl...@gmail.com> wrote:
> In case it is informative, here is the output from running zookeeper 3.8.0
> in my latest test run with NullMetricsProvider.
>
> ~/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin$ ./zkServer.sh
> start-foreground
> /usr/bin/java
> ZooKeeper JMX enabled by default
> Using config:
> /home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../conf/zoo.cfg
> 2022-08-28 21:36:13,846 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@177]
> - Reading configuration from:
> /home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../conf/zoo.cfg
> 2022-08-28 21:36:13,850 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@440]
> - clientPortAddress is 0.0.0.0:2181
> 2022-08-28 21:36:13,851 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@444]
> - secureClientPort is not set
> 2022-08-28 21:36:13,851 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@460]
> - observerMasterPort is not set
> 2022-08-28 21:36:13,851 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@477]
> - metricsProvider.className is
> org.apache.zookeeper.metrics.impl.NullMetricsProvider
> 2022-08-28 21:36:13,852 [myid:] - INFO
> [main:o.a.z.s.DatadirCleanupManager@78] - autopurge.snapRetainCount set
> to
> 3
> 2022-08-28 21:36:13,852 [myid:] - INFO
> [main:o.a.z.s.DatadirCleanupManager@79] - autopurge.purgeInterval set to
> 0
> 2022-08-28 21:36:13,852 [myid:] - INFO
> [main:o.a.z.s.DatadirCleanupManager@101] - Purge task is not scheduled.
> 2022-08-28 21:36:13,852 [myid:] - WARN [main:o.a.z.s.q.QuorumPeerMain@139
> ]
> - Either no config or no quorum defined in config, running in standalone
> mode
> 2022-08-28 21:36:13,853 [myid:] - INFO [main:o.a.z.j.ManagedUtil@46] -
> Log4j 1.2 jmx support not found; jmx disabled.
> 2022-08-28 21:36:13,853 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@177]
> - Reading configuration from:
> /home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../conf/zoo.cfg
> 2022-08-28 21:36:13,854 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@440]
> - clientPortAddress is 0.0.0.0:2181
> 2022-08-28 21:36:13,854 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@444]
> - secureClientPort is not set
> 2022-08-28 21:36:13,854 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@460]
> - observerMasterPort is not set
> 2022-08-28 21:36:13,854 [myid:] - INFO
> [main:o.a.z.s.q.QuorumPeerConfig@477]
> - metricsProvider.className is
> org.apache.zookeeper.metrics.impl.NullMetricsProvider
> 2022-08-28 21:36:13,854 [myid:] - INFO
> [main:o.a.z.s.ZooKeeperServerMain@123] - Starting server
> 2022-08-28 21:36:13,861 [myid:] - INFO [main:o.a.z.s.ServerMetrics@64] -
> ServerMetrics initialized with provider
> org.apache.zookeeper.metrics.impl.NullMetricsProvider@4d5d943d
> 2022-08-28 21:36:13,862 [myid:] - INFO
> [main:o.a.z.s.a.DigestAuthenticationProvider@47] - ACL digest algorithm
> is: SHA1
> 2022-08-28 21:36:13,862 [myid:] - INFO
> [main:o.a.z.s.a.DigestAuthenticationProvider@61] -
> zookeeper.DigestAuthenticationProvider.enabled = true
> 2022-08-28 21:36:13,863 [myid:] - INFO [main:o.a.z.s.p.FileTxnSnapLog@124
> ]
> - zookeeper.snapshot.trust.empty : false
> 2022-08-28 21:36:13,869 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> 2022-08-28 21:36:13,869 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> ______ _
> 2022-08-28 21:36:13,869 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> |___ / | |
> 2022-08-28 21:36:13,869 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> / / ___ ___ | | __ ___ ___ _ __ ___ _ __
> 2022-08-28 21:36:13,869 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> / / / _ \ / _ \ | |/ / / _ \ / _ \ | '_ \ / _ \ | '__|
> 2022-08-28 21:36:13,869 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> / /__ | (_) | | (_) | | < | __/ | __/ | |_) | | __/ | |
> 2022-08-28 21:36:13,870 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> /_____| \___/ \___/ |_|\_\ \___| \___| | .__/ \___| |_|
> 2022-08-28 21:36:13,870 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> | |
> 2022-08-28 21:36:13,870 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> |_|
> 2022-08-28 21:36:13,870 [myid:] - INFO [main:o.a.z.ZookeeperBanner@42] -
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server
>
> environment:zookeeper.version=3.8.0-5a02a05eddb59aee6ac762f7ea82e92a68eb9c0f,
> built on 2022-02-25 08:49 UTC
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:host.name=host
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:java.version=11.0.16
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:java.vendor=Ubuntu
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:java.home=/usr/lib/jvm/java-11-openjdk-amd64
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server
>
> environment:java.class.path=/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../zookeeper-server/target/classes:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../build/classes:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../zookeeper-server/target/lib/*.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../build/lib/*.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/zookeeper-prometheus-metrics-3.8.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/zookeeper-jute-3.8.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/zookeeper-3.8.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/snappy-java-1.1.7.7.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/slf4j-api-1.7.30.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/simpleclient_servlet-0.9.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/simpleclient_hotspot-0.9.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/simpleclient_common-0.9.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/simpleclient-0.9.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-transport-native-unix-common-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-transport-native-epoll-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-transport-classes-epoll-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-transport-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-tcnative-classes-2.0.48.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-tcnative-2.0.48.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-resolver-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-handler-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-common-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-codec-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/netty-buffer-4.1.73.Final.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/metrics-core-4.1.12.1.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/logback-core-1.2.10.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/logback-classic-1.2.10.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jline-2.14.6.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jetty-util-ajax-9.4.43.v20210629.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jetty-util-9.4.43.v20210629.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jetty-servlet-9.4.43.v20210629.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jetty-server-9.4.43.v20210629.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jetty-security-9.4.43.v20210629.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jetty-io-9.4.43.v20210629.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jetty-http-9.4.43.v20210629.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/javax.servlet-api-3.1.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jackson-databind-2.13.1.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jackson-core-2.13.1.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/jackson-annotations-2.13.1.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/commons-io-2.11.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/commons-cli-1.4.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../lib/audience-annotations-0.12.0.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../zookeeper-*.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../zookeeper-server/src/main/resources/lib/*.jar:/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin/../conf:
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server
>
> environment:java.library.path=/usr/java/packages/lib:/usr/lib/x86_64-linux-gnu/jni:/lib/x86_64-linux-gnu:/usr/lib/x86_64-linux-gnu:/usr/lib/jni:/lib:/usr/lib
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:java.io.tmpdir=/tmp
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:java.compiler=<NA>
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:os.name=Linux
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:os.arch=amd64
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:os.version=5.15.0-46-generic
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server
>
> environment:user.dir=/home/will/servers/zookeeper/apache-zookeeper-3.8.0-bin/bin
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:os.memory.free=231MB
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:os.memory.max=1000MB
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.Environment@98] -
> Server environment:os.memory.total=250MB
> 2022-08-28 21:36:13,871 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@140]
> - zookeeper.enableEagerACLCheck = false
> 2022-08-28 21:36:13,872 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@153]
> - zookeeper.digest.enabled = true
> 2022-08-28 21:36:13,872 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@157]
> - zookeeper.closeSessionTxn.enabled = true
> 2022-08-28 21:36:13,872 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@1496
> ]
> - zookeeper.flushDelay = 0 ms
> 2022-08-28 21:36:13,872 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@1505
> ]
> - zookeeper.maxWriteQueuePollTime = 0 ms
> 2022-08-28 21:36:13,872 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@1514
> ]
> - zookeeper.maxBatchSize=1000
> 2022-08-28 21:36:13,872 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@264]
> - zookeeper.intBufferStartingSizeBytes = 1024
> 2022-08-28 21:36:13,872 [myid:] - INFO [main:o.a.z.s.BlueThrottle@141] -
> Weighed connection throttling is disabled
> 2022-08-28 21:36:13,873 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@1297
> ]
> - minSessionTimeout set to 4000 ms
> 2022-08-28 21:36:13,873 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@1306
> ]
> - maxSessionTimeout set to 40000 ms
> 2022-08-28 21:36:13,874 [myid:] - INFO [main:o.a.z.s.ResponseCache@45] -
> getData response cache size is initialized with value 400.
> 2022-08-28 21:36:13,874 [myid:] - INFO [main:o.a.z.s.ResponseCache@45] -
> getChildren response cache size is initialized with value 400.
> 2022-08-28 21:36:13,874 [myid:] - INFO
> [main:o.a.z.s.u.RequestPathMetricsCollector@109] -
> zookeeper.pathStats.slotCapacity = 60
> 2022-08-28 21:36:13,874 [myid:] - INFO
> [main:o.a.z.s.u.RequestPathMetricsCollector@110] -
> zookeeper.pathStats.slotDuration = 15
> 2022-08-28 21:36:13,875 [myid:] - INFO
> [main:o.a.z.s.u.RequestPathMetricsCollector@111] -
> zookeeper.pathStats.maxDepth = 6
> 2022-08-28 21:36:13,875 [myid:] - INFO
> [main:o.a.z.s.u.RequestPathMetricsCollector@112] -
> zookeeper.pathStats.initialDelay = 5
> 2022-08-28 21:36:13,875 [myid:] - INFO
> [main:o.a.z.s.u.RequestPathMetricsCollector@113] -
> zookeeper.pathStats.delay = 5
> 2022-08-28 21:36:13,875 [myid:] - INFO
> [main:o.a.z.s.u.RequestPathMetricsCollector@114] -
> zookeeper.pathStats.enabled = false
> 2022-08-28 21:36:13,876 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@1533
> ]
> - The max bytes for all large requests are set to 104857600
> 2022-08-28 21:36:13,876 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@1547
> ]
> - The large request threshold is set to -1
> 2022-08-28 21:36:13,877 [myid:] - INFO
> [main:o.a.z.s.AuthenticationHelper@66] - zookeeper.enforce.auth.enabled =
> false
> 2022-08-28 21:36:13,877 [myid:] - INFO
> [main:o.a.z.s.AuthenticationHelper@67] - zookeeper.enforce.auth.schemes =
> []
> 2022-08-28 21:36:13,877 [myid:] - INFO [main:o.a.z.s.ZooKeeperServer@365]
> - Created server with tickTime 2000 ms minSessionTimeout 4000 ms
> maxSessionTimeout 40000 ms clientPortListenBacklog -1 datadir
> /tmp/zookeeper/3.8.0/version-2 snapdir /tmp/zookeeper/3.8.0/version-2
> 2022-08-28 21:36:13,890 [myid:] - INFO [main:o.e.j.u.l.Log@170] - Logging
> initialized @348ms to org.eclipse.jetty.util.log.Slf4jLog
> 2022-08-28 21:36:13,929 [myid:] - WARN [main:o.e.j.s.h.ContextHandler@1656
> ]
> - o.e.j.s.ServletContextHandler@3cebbb30{/,null,STOPPED} contextPath ends
> with /*
> 2022-08-28 21:36:13,930 [myid:] - WARN [main:o.e.j.s.h.ContextHandler@1667
> ]
> - Empty contextPath
> 2022-08-28 21:36:13,951 [myid:] - INFO [main:o.e.j.s.Server@375] -
> jetty-9.4.43.v20210629; built: 2021-06-30T11:07:22.254Z; git:
> 526006ecfa3af7f1a27ef3a288e2bef7ea9dd7e8; jvm
> 11.0.16+8-post-Ubuntu-0ubuntu120.04
> 2022-08-28 21:36:13,967 [myid:] - INFO
> [main:o.e.j.s.s.DefaultSessionIdManager@334] - DefaultSessionIdManager
> workerName=node0
> 2022-08-28 21:36:13,967 [myid:] - INFO
> [main:o.e.j.s.s.DefaultSessionIdManager@339] - No SessionScavenger set,
> using defaults
> 2022-08-28 21:36:13,968 [myid:] - INFO [main:o.e.j.s.s.HouseKeeper@132] -
> node0 Scavenging every 600000ms
> 2022-08-28 21:36:13,970 [myid:] - WARN
> [main:o.e.j.s.ConstraintSecurityHandler@759] -
> ServletContext@o.e.j.s.ServletContextHandler@3cebbb30{/,null,STARTING} has
> uncovered http methods for path: /*
> 2022-08-28 21:36:13,975 [myid:] - INFO [main:o.e.j.s.h.ContextHandler@915
> ]
> - Started o.e.j.s.ServletContextHandler@3cebbb30{/,null,AVAILABLE}
> 2022-08-28 21:36:13,983 [myid:] - INFO [main:o.e.j.s.AbstractConnector@331
> ]
> - Started ServerConnector@29d89d5d{HTTP/1.1, (http/1.1)}{0.0.0.0:8080}
> 2022-08-28 21:36:13,983 [myid:] - INFO [main:o.e.j.s.Server@415] -
> Started
> @441ms
> 2022-08-28 21:36:13,983 [myid:] - INFO
> [main:o.a.z.s.a.JettyAdminServer@196]
> - Started AdminServer on address 0.0.0.0, port 8080 and command URL
> /commands
> 2022-08-28 21:36:13,986 [myid:] - INFO [main:o.a.z.s.ServerCnxnFactory@169
> ]
> - Using org.apache.zookeeper.server.NIOServerCnxnFactory as server
> connection factory
> 2022-08-28 21:36:13,987 [myid:] - WARN [main:o.a.z.s.ServerCnxnFactory@309
> ]
> - maxCnxns is not configured, using default value 0.
> 2022-08-28 21:36:13,988 [myid:] - INFO
> [main:o.a.z.s.NIOServerCnxnFactory@652] - Configuring NIO connection
> handler with 10s sessionless connection timeout, 2 selector thread(s), 24
> worker threads, and 64 kB direct buffers.
> 2022-08-28 21:36:13,988 [myid:] - INFO
> [main:o.a.z.s.NIOServerCnxnFactory@660] - binding to port
> 0.0.0.0/0.0.0.0:2181
> 2022-08-28 21:36:13,997 [myid:] - INFO
> [main:o.a.z.s.w.WatchManagerFactory@42] - Using
> org.apache.zookeeper.server.watch.WatchManager as watch manager
> 2022-08-28 21:36:13,997 [myid:] - INFO
> [main:o.a.z.s.w.WatchManagerFactory@42] - Using
> org.apache.zookeeper.server.watch.WatchManager as watch manager
> 2022-08-28 21:36:13,998 [myid:] - INFO [main:o.a.z.s.ZKDatabase@132] -
> zookeeper.snapshotSizeFactor = 0.33
> 2022-08-28 21:36:13,998 [myid:] - INFO [main:o.a.z.s.ZKDatabase@152] -
> zookeeper.commitLogCount=500
> 2022-08-28 21:36:14,002 [myid:] - INFO [main:o.a.z.s.p.SnapStream@61] -
> zookeeper.snapshot.compression.method = CHECKED
>
> Also here is my 3.8.0 zoo.cfg file:
>
> # The number of milliseconds of each tick
> tickTime=2000
> # The number of ticks that the initial
> # synchronization phase can take
> initLimit=10
> # The number of ticks that can pass between
> # sending a request and getting an acknowledgement
> syncLimit=5
> # the directory where the snapshot is stored.
> # do not use /tmp for storage, /tmp here is just
> # example sakes.
> dataDir=/tmp/zookeeper/3.8.0
> # the port at which the clients will connect
> clientPort=2181
> # the maximum number of client connections.
> # increase this if you need to handle more clients
> #maxClientCnxns=60
> #
> # Be sure to read the maintenance section of the
> # administrator guide before turning on autopurge.
> #
> #
> https://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
> #
> # The number of snapshots to retain in dataDir
> #autopurge.snapRetainCount=3
> # Purge task interval in hours
> # Set to "0" to disable auto purge feature
> #autopurge.purgeInterval=1
>
> ## Metrics Providers
> #
> # https://prometheus.io Metrics Exporter
>
> #metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider
> #metricsProvider.httpHost=0.0.0.0
> #metricsProvider.httpPort=7000
> #metricsProvider.exportJvmInfo=true
>
> 4lw.commands.whitelist=*
> digest.enabled=true
>
>
> metricsProvider.className=org.apache.zookeeper.metrics.impl.NullMetricsProvider
>
