Hi Jun, Based on visual review of the log files, most of the time is spent in remoteTime.
Example: > grep Completed kafka-request.log.2014-01-30-01 | sed 's/^.*totalTime://' | > less ... 502,queueTime:1,localTime:1,remoteTime:499,sendTime:1 (kafka.request.logger) 502,queueTime:0,localTime:1,remoteTime:500,sendTime:1 (kafka.request.logger) 502,queueTime:1,localTime:0,remoteTime:500,sendTime:1 (kafka.request.logger) 502,queueTime:1,localTime:0,remoteTime:500,sendTime:1 (kafka.request.logger) 502,queueTime:1,localTime:1,remoteTime:500,sendTime:0 (kafka.request.logger) 503,queueTime:1,localTime:0,remoteTime:501,sendTime:1 (kafka.request.logger) 503,queueTime:1,localTime:1,remoteTime:501,sendTime:0 (kafka.request.logger) 502,queueTime:1,localTime:0,remoteTime:501,sendTime:0 (kafka.request.logger) 502,queueTime:1,localTime:0,remoteTime:501,sendTime:0 (kafka.request.logger) ... Some of the tests were executed with recommended configuration settings copied from the product webpage. These configuration settings included following lines for "replica": num.replica.fetchers=4 replica.fetch.max.bytes=1048576 replica.fetch.wait.max.ms=500 replica.high.watermark.checkpoint.interval.ms=5000 replica.socket.timeout.ms=30000 replica.socket.receive.buffer.bytes=65536 replica.lag.time.max.ms=10000 replica.lag.max.messages=4000 In most cases the tests were executed with "out-of-box" settings, which don't change "replica" configuration. We are running these tests on very weak machines. If absolute throughput numbers are not as high as in other people's tests, that's understandable. The main concern is why throughput drops 4-10 times when a number of expected acks is not 1. Should we wait for newer versions of Kafka and settle with acks=1 for now? Thank you, Michael Popov -----Original Message----- From: Jun Rao [mailto:[email protected]] Sent: Friday, January 31, 2014 8:57 PM To: [email protected] Subject: Re: Kafka performance test: "--request-num-acks -1" kills throughput The request log shows you the breakdown of the request time. Where is most of the time spent? Also, did you change replica.fetch.wait.max.ms in the broker? Thanks, Jun On Fri, Jan 31, 2014 at 10:14 AM, Michael Popov <[email protected]>wrote: > Hi Jun, > > The usage output of bin/kafka-producer-perf-test.sh shows > > --request-timeout-ms <Integer> The produce request timeout in ms > > (default: 3000) > > In my test runs I used the following command-line arguments: > > bin/kafka-producer-perf-test.sh --broker-list 10.0.0.8:9092, > 10.0.0.10:9092 --compression-codec 0 --message-size 1024 > --request-num-acks -1 --sync --messages 100000 -threads 1 > --show-detailed-stats --reporting-interval 1000 --topics d2111 | grep > -v "at " > > I assume producer uses default timeout of 3000ms in my tests. > > I ran a few data processing operations on kafka-request.log.* > > grep Completed kafka-request.log.2014-01-30-17 | sed 's/^.*totalTime://' > | sed 's/,.*$//' > /tmp/times.log > cat /tmp/times.log | sort -k 1n | uniq > /tmp/result.log tail > /tmp/result.log > 5643 > 5761 > 5834 > 6319 > 6320 > 6535 > 8407 > 8554 > 9422 > 9502 > > I guess that means some of Fetch requests from the leader broker to > the follower broker took much longer than 3000ms. That explains > expired producer's requests and probably the overall decrease of the > throughput in tests with acksNum!=1. > > What may cause such long responses? Is there a way to address this issue? > > Thank you, > Michael Popov > > > > -----Original Message----- > From: Jun Rao [mailto:[email protected]] > Sent: Friday, January 31, 2014 7:52 AM > To: [email protected] > Subject: Re: Kafka performance test: "--request-num-acks -1" kills > throughput > > Michael, > > Those SocketTimeoutExceptions meas that the producer didn't receive > the response from the broker in time. Could you check the request log > in the broker and see what the request completion time is and how it > compares with the request socket timeout? > > I did some testing a while back. Latency wise, ack=-1 is about twice > that of ack=1 since it requires an extra network round trip. > > Thanks, > > Jun > > > On Thu, Jan 30, 2014 at 11:23 AM, Michael Popov <[email protected] > >wrote: > > > Hi Jun, > > > > I ran a new new tests today. > > > > Settings: 2 Kafka brokers, 1 Zookeeper node, 4 client machines. > > Creating a new topic with 1 partition for each client process. > > Commands to create a topic looked like this one: > > > > bin/kafka-create-topic.sh --partition 1 --replica 2 --zookeeper > > 10.0.0.4:2181 --topic d1 > > > > Commands to run a test producer looked like this: > > > > bin/kafka-producer-perf-test.sh --broker-list 10.0.0.8:9092, > > 10.0.0.10:9092 --compression-codec 0 --message-size 1024 > > --request-num-acks 1 --sync --messages 100000 -threads 10 > > --show-detailed-stats --reporting-interval 1000 --topics d1 | grep > > -v > "at " > > > > Results of 4 test runs: > > ====================================== > > --request-num-acks -1 > > ===================================== > > 2014-01-30 17:55:01:576, 2014-01-30 17:59:23:294, 0, 1024, 200, > > 97.66, 0.3731, 100000, 382.0906 > > 2014-01-30 17:55:01:921, 2014-01-30 18:20:56:952, 0, 1024, 200, > > 97.66, 0.0628, 99999, 64.3068 > > 2014-01-30 17:55:00:037, 2014-01-30 18:20:57:164, 0, 1024, 200, > > 97.66, 0.0627, 100000, 64.2208 > > 2014-01-30 17:54:59:723, 2014-01-30 18:20:34:633, 0, 1024, 200, > > 97.66, 0.0636, 100000, 65.1504 > > > > ====================================== > > --request-num-acks 1 > > ===================================== > > 2014-01-30 18:24:54:588, 2014-01-30 18:27:42:408, 0, 1024, 200, > > 97.66, 0.5819, 100000, 595.8765 > > 2014-01-30 18:24:54:830, 2014-01-30 18:27:24:080, 0, 1024, 200, > > 97.66, 0.6543, 100000, 670.0168 > > 2014-01-30 18:24:52:855, 2014-01-30 18:25:48:119, 0, 1024, 200, > > 97.66, 1.7671, 100000, 1809.4962 > > 2014-01-30 18:24:52:763, 2014-01-30 18:27:45:675, 0, 1024, 200, > > 97.66, 0.5648, 100000, 578.3289 > > > > ====================================== > > --request-num-acks -1 > > ===================================== > > 2014-01-30 18:31:08:756, 2014-01-30 18:57:12:123, 0, 1024, 200, > > 97.66, 0.0625, 99998, 63.9632 > > 2014-01-30 18:31:08:860, 2014-01-30 18:37:18:634, 0, 1024, 200, > > 97.66, 0.2641, 100000, 270.4355 > > 2014-01-30 18:31:06:968, 2014-01-30 18:57:28:389, 0, 1024, 200, > > 97.66, 0.0618, 99999, 63.2336 > > 2014-01-30 18:31:06:819, 2014-01-30 18:37:19:703, 0, 1024, 200, > > 97.66, 0.2619, 100000, 268.1799 > > > > ====================================== > > --request-num-acks 1 > > ===================================== > > 2014-01-30 19:02:35:171, 2014-01-30 19:05:21:650, 0, 1024, 200, > > 97.66, 0.5866, 100000, 600.6764 > > 2014-01-30 19:02:40:264, 2014-01-30 19:05:01:863, 0, 1024, 200, > > 97.66, 0.6897, 100000, 706.2197 > > 2014-01-30 19:02:38:537, 2014-01-30 19:03:27:687, 0, 1024, 200, > > 97.66, 1.9869, 100000, 2034.5880 > > 2014-01-30 19:02:33:384, 2014-01-30 19:04:51:134, 0, 1024, 200, > > 97.66, 0.7089, 100000, 725.9528 > > > > > > There is something seriously wrong with Kafka throughput in "2acks" > tests. > > Anything I can do to resolve this issue? > > > > One more thing. Producers kept printing error messages like this > > during the test runs: > > [2014-01-30 18:32:39,777] WARN Failed to send producer request with > > correlation id 51676 to broker 1 with data for partitions [d4111,0] > > (kafka.producer.async.DefaultEventHandler) > > java.net.SocketTimeoutException > > [2014-01-30 18:32:53,308] WARN Produce request with correlation id > > 57999 failed due to [d4111,0]: kafka.common.RequestTimedOutException > > (kafka.producer.async.DefaultEventHandler) > > [2014-01-30 18:33:22,350] WARN Failed to send producer request with > > correlation id 72096 to broker 1 with data for partitions [d4111,0] > > (kafka.producer.async.DefaultEventHandler) > > java.net.SocketTimeoutException > > [2014-01-30 18:33:39,740] WARN Failed to send producer request with > > correlation id 81147 to broker 1 with data for partitions [d4111,0] > > (kafka.producer.async.DefaultEventHandler) > > java.net.SocketTimeoutException > > > > Thank you, > > Michael Popov > > > > > > -----Original Message----- > > From: Jun Rao [mailto:[email protected]] > > Sent: Wednesday, January 29, 2014 9:01 PM > > To: [email protected] > > Subject: Re: Kafka performance test: "--request-num-acks -1" kills > > throughput > > > > Does the result change with just 1 partition? > > > > Thanks, > > > > Jun > > > > > > On Wed, Jan 29, 2014 at 4:06 PM, Michael Popov > > <[email protected]> > > wrote: > > > > > Hi, > > > > > > We need a reliable low-latency message queue that can scale. Kafka > > > looks like a right system for this role. > > > > > > I am running performance tests on multiple platforms: Linux and > Windows. > > > For test purposes I create topics with 2 replicas and multiple > > partitions. > > > In all deployments running test producers that wait for both replicas' > > > acks practically kills Kafka throughput. For example, on the > > > following deployment on Linux machines: 2 Kafka brokers, 1 > > > Zookeeper node, 4 client hosts to create load, 4 topics with 10 > > > partitions each and 2 replicas > > > > > > - running tests with "--request-num-acks 1" produces ~3,600 > > > msgs/sec > > > > > > - running tests with "--request-num-acks -1" produces ~348 > > > msgs/sec > > > > > > > > > Here is output of one of the four concurrent processes: > > > > > > [User@Client2 kafka_2.8.0-0.8.0]$ bin/kafka-producer-perf-test.sh > > > --broker-list 10.0.0.8:9092,10.0.0.10:9092 --compression-codec 0 > > > --message-size 1024 --request-num-acks -1 --sync --messages 100000 > > > -threads > > > 10 --show-detailed-stats --reporting-interval 1000 --topics c12 | > > > grep -v "at " > > > start.time, end.time, compression, message.size, batch.size, > > > total.data.sent.in.MB, MB.sec, total.data.sent.in.nMsg, nMsg.sec > > > [2014-01-29 23:21:16,720] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,825] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,830] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,831] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,839] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,841] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,847] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,858] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,862] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:21:16,867] WARN Property reconnect.interval is not > > > valid > > > (kafka.utils.VerifiableProperties) > > > [2014-01-29 23:32:03,830] WARN Produce request with correlation id > > > 11467 failed due to [c12,2]: kafka.common.RequestTimedOutException > > > (kafka.producer.async.DefaultEventHandler) > > > [2014-01-29 23:32:03,831] WARN Produce request with correlation id > > > 11859 failed due to [c12,8]: kafka.common.RequestTimedOutException > > > (kafka.producer.async.DefaultEventHandler) > > > [2014-01-29 23:32:03,831] WARN Failed to send producer request > > > with correlation id 11819 to broker 0 with data for partitions > > > [c12,8] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > [2014-01-29 23:32:03,834] WARN Failed to send producer request > > > with correlation id 11315 to broker 0 with data for partitions > > > [c12,6] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > [2014-01-29 23:32:03,834] WARN Failed to send producer request > > > with correlation id 11191 to broker 0 with data for partitions > > > [c12,4] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > [2014-01-29 23:32:03,834] WARN Failed to send producer request > > > with correlation id 11791 to broker 0 with data for partitions > > > [c12,4] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > [2014-01-29 23:32:03,834] WARN Failed to send producer request > > > with correlation id 11395 to broker 0 with data for partitions > > > [c12,6] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > [2014-01-29 23:32:03,834] WARN Failed to send producer request > > > with correlation id 11631 to broker 0 with data for partitions > > > [c12,4] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > [2014-01-29 23:32:03,834] WARN Failed to send producer request > > > with correlation id 10563 to broker 0 with data for partitions > > > [c12,0] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > [2014-01-29 23:32:03,834] WARN Failed to send producer request > > > with correlation id 10907 to broker 0 with data for partitions > > > [c12,2] > > > (kafka.producer.async.DefaultEventHandler) > > > java.net.SocketTimeoutException > > > 2014-01-29 23:21:16:562, 2014-01-29 23:40:15:886, 0, 1024, 200, > > > 97.66, 0.0857, 100000, 87.7713 > > > > > > The test result is consistent and reproducible in all deployments: > > > numbers can vary but changing acks setting consistently reduces > > > Kafka throughput > > > 4-10 times. > > > > > > Is it expected system behavior? Any tuning options to resolve the > > problem? > > > > > > Thank you, > > > Michael Popov > > > > > > > > >
