Yes, we can expose a user callback in MM, just like we did for rebalance listener. I still think ErrorLoggingCallback needs some change, though. Can we only store the value bytes when logAsString is set to true? That looks more reasonable to me.
Jiangjie (Becket) Qin On 6/21/15, 3:02 AM, "tao xiao" <xiaotao...@gmail.com> wrote: >Yes, I agree with that. It is even better if we can supply our own >callback. For people who want to view the content of message when failure >they still can do so > >On Sun, Jun 21, 2015 at 2:20 PM Guozhang Wang <wangg...@gmail.com> wrote: > >> Hi Tao / Jiangjie, >> >> I think a better fix here may be not letting >>MirrorMakerProducerCallback to >> extend from ErrorLoggingCallback, but rather change the >> ErrorLoggingCallback itself as it defeats the usage of logAsString, >>which I >> think is useful for a general error logging purposes. Rather we can >> let MirrorMakerProducerCallback >> to not take the value bytes itself but just the length if people agree >>that >> for MM we probably are not interested in its message value in callback. >> Thoughts? >> >> Guozhang >> >> On Wed, Jun 17, 2015 at 1:06 AM, tao xiao <xiaotao...@gmail.com> wrote: >> >> > Thank you for the reply. >> > >> > Patch submitted https://issues.apache.org/jira/browse/KAFKA-2281 >> > >> > On Mon, 15 Jun 2015 at 02:16 Jiangjie Qin <j...@linkedin.com.invalid> >> > wrote: >> > >> > > Hi Tao, >> > > >> > > Yes, the issue that ErrorLoggingCallback keeps value as local >>variable >> is >> > > known for a while and we probably should fix it as the value is not >> used >> > > except logging the its size. Can you open a ticket and maybe also >> submit >> > a >> > > patch? >> > > >> > > For unreachable objects I don¹t think it is memory leak. As you >>said, >> GC >> > > should take care of this. In LinkedIn we are using G1GC with some >> tunings >> > > made by our SRE. You can try that if interested. >> > > >> > > Thanks, >> > > >> > > Jiangjie (Becket) Qin >> > > >> > > On 6/13/15, 11:39 AM, "tao xiao" <xiaotao...@gmail.com> wrote: >> > > >> > > >Hi, >> > > > >> > > >I am using mirror maker in trunk to replica data across two data >> > centers. >> > > >While the destination broker was having busy load and unresponsive >>the >> > > >send >> > > >rate of mirror maker was very low and the available producer buffer >> was >> > > >quickly filled up. At the end mirror maker threw OOME. Detailed >> > exception >> > > >can be found here >> > > > >> > > >> > >> >>https://gist.github.com/xiaotao183/53e1bf191c1a4d030a25#file-oome-excepti >>o >> > > >n-L1 >> > > > >> > > >I started up mirror maker with 1G memory and 256M producer buffer. >>I >> > used >> > > >eclipse MAT to analyze the heap dump and found out the retained >>heap >> > size >> > > >of all RecordBatch objects were more than 500MB half of which were >> used >> > to >> > > >retain data that were to send to destination broker which makes >>sense >> to >> > > >me >> > > >as it is close to 256MB producer buffer but the other half of which >> were >> > > >used by kafka.tools.MirrorMaker$MirrorMakerProducerCallback. As >>every >> > > >producer callback in mirror maker takes the message value and hold >>it >> > > >until >> > > >the message is successfully delivered. In my case since the >> destination >> > > >broker was very unresponsive the message value held by callback >>would >> > stay >> > > >forever which I think is a waste and it is a major contributor to >>the >> > OOME >> > > >issue. screenshot of MAT >> > > > >> > > >> > >> >>https://gist.github.com/xiaotao183/53e1bf191c1a4d030a25#file-mat-screensh >>o >> > > >t-png >> > > > >> > > >The other interesting problem I observed is that when I turned on >> > > >unreachable object parsing in MAT more than 400MB memory was >>occupied >> by >> > > >unreachable objects. It surprised me that gc didn't clean them up >> before >> > > >OOME was thrown. As suggested in gc log >> > > > >> > > >> > >> >>https://gist.github.com/xiaotao183/53e1bf191c1a4d030a25#file-oome-gc-log- >>L >> > > >1 >> > > >Full GC was unable to reclaim any memory and when facing OOME these >> > > >unreachable objects should have been cleaned up. so either eclipse >>MAT >> > has >> > > >issue parsing the heap dump or there is hidden memory leak that is >> hard >> > to >> > > >find. I attached the sample screenshot of the unreachable objects >>here >> > > > >> > > >> > >> >>https://gist.github.com/xiaotao183/53e1bf191c1a4d030a25#file-unreachable- >>o >> > > >bjects-png >> > > > >> > > >The consumer properties >> > > > >> > > >zookeeper.connect=zk >> > > >zookeeper.connection.timeout.ms=1000000 >> > > >group.id=mm >> > > >auto.offset.reset=smallest >> > > >partition.assignment.strategy=roundrobin >> > > > >> > > >The producer properties >> > > > >> > > >bootstrap.servers=brokers >> > > >client.id=mirror-producer >> > > >producer.type=async >> > > >compression.codec=none >> > > >serializer.class=kafka.serializer.DefaultEncoder >> > > >> >>>key.serializer=org.apache.kafka.common.serialization.ByteArraySerializer >> > > >> > >> >>>value.serializer=org.apache.kafka.common.serialization.ByteArraySerializ >>>er >> > > >buffer.memory=268435456 >> > > >batch.size=1048576 >> > > >max.request.size=5242880 >> > > >send.buffer.bytes=1048576 >> > > > >> > > >The java command to start mirror maker >> > > >java -Xmx1024M -Xms512M -XX:+HeapDumpOnOutOfMemoryError >> > > >-XX:HeapDumpPath=/home/kafka/slc-phx-mm-cg.hprof >> > > >-XX:+PrintTenuringDistribution -XX:MaxTenuringThreshold=3 -server >> > > >-XX:+UseParNewGC -XX:+UseConcMarkSweepGC >>-XX:+CMSClassUnloadingEnabled >> > > >-XX:+CMSScavengeBeforeRemark -XX:+DisableExplicitGC >> > > >-Djava.awt.headless=true >> > > >-Xloggc:/var/log/kafka/kafka-phx/cg/mirrormaker-gc.log -verbose:gc >> > > >-XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps >> > > >-XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 >> > > >-XX:GCLogFileSize=10M -Dcom.sun.management.jmxremote >> > > >-Dcom.sun.management.jmxremote.authenticate=false >> > > >-Dcom.sun.management.jmxremote.ssl=false >> > > >-Dkafka.logs.dir=/var/log/kafka/kafka-phx/cg >> > > >> > >> >>>-Dlog4j.configuration=file:/usr/share/kafka/bin/../config/tools-log4j.pr >>>op >> > > >erties >> > > >-cp libs/* kafka.tools.MirrorMaker --consumer.config >> > > >consumer.properties --num.streams 10 --producer.config >> > > >producer.properties --whitelist test.* >> > > >> > > >> > >> >> >> >> -- >> -- Guozhang >>
