Using the little bash script in that JIRA ticket to go thru the GC log and sum up the total pause times I come up with the following. I don't see anything that would indicate a ~28 second pause.
2017-01-12T07:00 = 72.2961 > 2017-01-12T07:01 = 59.8112 > 2017-01-12T07:02 = 69.6915 > 2017-01-12T07:03 = 74.4093 > 2017-01-12T07:04 = 73.507 > 2017-01-12T07:05 = 73.7028 > 2017-01-12T07:06 = 72.3392 > 2017-01-12T07:07 = 70.502 > 2017-01-12T07:08 = 71.7471 > 2017-01-12T07:09 = 76.8371 > 2017-01-12T07:10 = 72.3836 > 2017-01-12T07:11 = 74.7462 > 2017-01-12T07:12 = 57.1328 > 2017-01-12T07:13 = 80.005 > 2017-01-12T07:14 = 76.0012 > 2017-01-12T07:15 = 79.2221 > 2017-01-12T07:16 = 57.5385 > 2017-01-12T07:17 = 58.1185 > 2017-01-12T07:18 = 72.0524 > 2017-01-12T07:19 = 110.6736 > 2017-01-12T07:20 = 64.9808 > 2017-01-12T07:21 = 66.8767 > 2017-01-12T07:22 = 32.409 > 2017-01-12T07:23 = 85.3671 > 2017-01-12T07:24 = 123.9212 > 2017-01-12T07:25 = 70.3219 > On Thu, Jan 12, 2017 at 10:49 AM, Stephen Powis <spo...@salesforce.com> wrote: > Just realized that GCEasy doesn't keep reports around for very long > anymore, here is a screencap of the report: http://imgur.com/a/MEubD > > The longest reported GC pause was 30ms, tho they happen somewhat > frequently at an average of once per 12 seconds. KAFKA-4616 certainly > sounds just like my scenario, but I'm having trouble finding the long GC > pauses described in that ticket in my own logs. > > On Thu, Jan 12, 2017 at 10:42 AM, tao xiao <xiaotao...@gmail.com> wrote: > >> You may run into this bug https://issues.apache.org/jira >> /browse/KAFKA-4614 >> >> On Thu, 12 Jan 2017 at 23:38 Stephen Powis <spo...@salesforce.com> wrote: >> >> > Per my email to the list in Sept, when I reviewed GC logs then, I didn't >> > see anything out of the ordinary. ( >> > >> > http://mail-archives.apache.org/mod_mbox/kafka-users/201609. >> mbox/%3CCABQB-gS7h4Nuq3TKgHoAVeRHPWnBNs2B0Tz0kCjmdB9c0SDcLQ% >> 40mail.gmail.com%3E >> > ) >> > >> > Reviewing the GC logs from this morning around the timestamp in my >> previous >> > email, I see GC running roughly every 10-12 seconds, with total times >> > similar to the following: >> > >> > 2017-01-12T07:16:46.867-0500: 46891.844: Total time for which >> application >> > > threads were stopped: 0.0141281 seconds, Stopping threads took: >> 0.0002171 >> > > seconds >> > > >> > > >> > Here is a link to a GCEasy report: >> > >> > http://gceasy.io/my-gc-report.jsp?p=c2hhcmVkLzIwMTcvMDEvMTIv >> LS10b3RhbEdDLWthZmthMS00LmxvZy5nei0tMTUtMzQtNTk= >> > >> > >> > Currently using G1 gc with the following settings: >> > >> > -Xmx12G -Xms12G -server -XX:MaxPermSize=48M -verbose:gc >> > -Xloggc:/var/log/kafka/gc.log -XX:+PrintGCDateStamps -XX:+PrintGCDetails >> > -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime >> > -XX:+PrintTLAB -XX:+DisableExplicitGC -XX:+UseGCLogFileRotation >> > -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=100M -XX:+UseCompressedOops >> > -XX:+AlwaysPreTouch -XX:+UseG1GC -XX:MaxGCPauseMillis=20 >> > -XX:+HeapDumpOnOutOfMemoryError >> > -XX:HeapDumpPath=/var/log/kafka/heapDump.log >> > -Xloggc:/opt/kafka/current/bin/../logs/kafkaServer-gc.log -verbose:gc >> > -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps >> > >> > >> > >> > On Thu, Jan 12, 2017 at 9:55 AM, Tauzell, Dave < >> > dave.tauz...@surescripts.com >> > > wrote: >> > >> > > Can you collect garbage collection stats and verify there isn't a >> long GC >> > > happening at the same time? >> > > >> > > -Dave >> > > >> > > -----Original Message----- >> > > From: Stephen Powis [mailto:spo...@salesforce.com] >> > > Sent: Thursday, January 12, 2017 8:34 AM >> > > To: users@kafka.apache.org >> > > Subject: Re: Taking a long time to roll a new log segment (~1 min) >> > > >> > > So per the kafka docs I up'd our FD limit to 100k, and we are no >> longer >> > > seeing the process die, which is good. >> > > >> > > Unfortunately we're still seeing very high log segment roll times, and >> > I'm >> > > unsure if this is considered 'normal', as it tends to block producers >> > > during this period. >> > > >> > > We are running kafka 0.10.0.1, but I patched in some additionally >> timing >> > > statements into the kafka.log.log roll() method to narrow down exactly >> > > which part of that method is taking so long. >> > > >> > > Again, typically the process to roll a new log file takes only 1-2ms >> > tops, >> > > but several times a day it takes 30-60+ seconds, across all of our >> > > brokers. I've narrowed it down to this bit of code causing the issue: >> > > https://github.com/apache/kafka/blob/0.10.0/core/src/ >> > > main/scala/kafka/log/Log.scala#L652-L658 >> > > >> > > Here's an example of output w/ my additional timing log statements: >> > > >> > > [2017-01-12 07:17:58,199] INFO Rolled new log segment for 'MyTopic-4' >> in >> > > > 28028 ms. (kafka.log.Log) >> > > >> > > [2017-01-12 07:17:58,200] INFO LastEntry match time 'EventStream-4' in >> > > > 28027 ms. (kafka.log.Log) >> > > > >> > > >> > > Any thoughts? Help? This considered normal? >> > > >> > > Thanks >> > > Stephen >> > > >> > > >> > > On Tue, Jan 10, 2017 at 2:37 AM, Ewen Cheslack-Postava < >> > e...@confluent.io> >> > > wrote: >> > > >> > > > I can't speak to the exact details of why fds would be kept open >> > > > longer in that specific case, but are you aware that the >> > > > recommendation for production clusters for open fd limits is much >> > > > higher? It's been suggested to be 100,000 as a starting point for >> quite >> > > awhile: >> > > > http://kafka.apache.org/documentation.html#os >> > > > >> > > > -Ewen >> > > > >> > > > On Mon, Jan 9, 2017 at 12:45 PM, Stephen Powis < >> spo...@salesforce.com> >> > > > wrote: >> > > > >> > > > > Hey! >> > > > > >> > > > > I've run into something concerning in our production cluster....I >> > > > > believe I've posted this question to the mailing list previously ( >> > > > > http://mail-archives.apache.org/mod_mbox/kafka-users/201609. >> mbox/bro >> > > > > wser >> > > > ) >> > > > > but the problem has become considerably more serious. >> > > > > >> > > > > We've been fighting issues where Kafka 0.10.0.1 hits its max file >> > > > > descriptor limit. Our limit is set to ~16k, and under normal >> > > > > operation >> > > > it >> > > > > holds steady around 4k open files. >> > > > > >> > > > > But occasionally Kafka will roll a new log segment, which >> typically >> > > > > takes on the order of magnitude of a few milliseconds. >> > > > > However...sometimes it will take a considerable amount of time, >> any >> > > > > where from 40 seconds up to over a minute. When this happens, it >> > > > > seems like connections are not released by kafka, and we end up >> with >> > > > > thousands of client connections >> > > > stuck >> > > > > in CLOSE_WAIT, which pile up and exceed our max file descriptor >> > limit. >> > > > > This happens all in the span of about a minute. >> > > > > >> > > > > Our logs look like this: >> > > > > >> > > > > [2017-01-08 01:10:17,117] INFO Rolled new log segment for >> > > > > 'MyTopic-8' in >> > > > > > 41122 ms. (kafka.log.Log) >> > > > > > [2017-01-08 01:10:32,550] INFO Rolled new log segment for >> > 'MyTopic-4' >> > > > in >> > > > > 1 >> > > > > > ms. (kafka.log.Log) >> > > > > > [2017-01-08 01:11:10,039] INFO [Group Metadata Manager on Broker >> > 4]: >> > > > > > Removed 0 expired offsets in 0 milliseconds. >> > > > > > (kafka.coordinator.GroupMetadataManager) >> > > > > > [2017-01-08 01:19:02,877] ERROR Error while accepting connection >> > > > > > (kafka.network.Acceptor) >> > > > > > java.io.IOException: Too many open files at >> > > > > > sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) >> > > > > > >> > > > > at >> > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( >> > > > ServerSocketChannelImpl.java: >> > > > > 422) >> > > > > > at >> > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( >> > > > ServerSocketChannelImpl.java: >> > > > > 250) >> > > > > > at kafka.network.Acceptor.accept( >> SocketServer.scala:323) >> > > > > > at kafka.network.Acceptor.run(SocketServer.scala:268) >> > > > > > at java.lang.Thread.run(Thread.java:745) >> > > > > > [2017-01-08 01:19:02,877] ERROR Error while accepting connection >> > > > > > (kafka.network.Acceptor) >> > > > > > java.io.IOException: Too many open files >> > > > > > at sun.nio.ch.ServerSocketChannelImpl.accept0(Native >> > Method) >> > > > > > at >> > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( >> > > > ServerSocketChannelImpl.java: >> > > > > 422) >> > > > > > at >> > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( >> > > > ServerSocketChannelImpl.java: >> > > > > 250) >> > > > > > at kafka.network.Acceptor.accept( >> SocketServer.scala:323) >> > > > > > at kafka.network.Acceptor.run(SocketServer.scala:268) >> > > > > > at java.lang.Thread.run(Thread.java:745) >> > > > > > ..... >> > > > > > >> > > > > >> > > > > >> > > > > And then kafka crashes. >> > > > > >> > > > > Has anyone seen this behavior of slow log segmented being rolled? >> > > > > Any ideas of how to track down what could be causing this? >> > > > > >> > > > > Thanks! >> > > > > Stephen >> > > > > >> > > > >> > > This e-mail and any files transmitted with it are confidential, may >> > > contain sensitive information, and are intended solely for the use of >> the >> > > individual or entity to whom they are addressed. If you have received >> > this >> > > e-mail in error, please notify the sender by reply e-mail immediately >> and >> > > destroy all copies of the e-mail and any attachments. >> > > >> > >> > >
