[
https://issues.apache.org/jira/browse/AMQ-5077?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13956570#comment-13956570
]
Richard Wagg commented on AMQ-5077:
-----------------------------------
Hi,
I'm happy that those 2 changes would help the producer in not getting blocked
by the JMS.
It is also likely to improve throughput to the consumers, but i think we could
make further improvements there.
A new executor using Concurrent store and dispatch is likely to result in more
messages in flight to the consumers - but i'm still concerned that the
performance of this (this being the ultimate queue writes/sec the broker can
achieve) will be hard to determine, as it will be a function of how quick the
underlying disk store is as well as the average roundtrip time for the consumer
to receive, process and ACK each message. If we have a large queue of messages
being written to the diskstore, and relatively quick consumers, then we can
optimise away the disk writes - but i'm not sure that this is visible at the
moment.
I would still be interested in i guess some form of delay queue for the
diskstore writes - a configurable property for a minimum delay to wait before
writing messages through to the index/diskstore, which you could benchmark
against your expected consumer ACK roundtrip time to determine if you expect to
be able to optimise away the disk writes completely under most situations.
If this delay is small enough, and the producer window doesn't get decremented
till either the diskstore write completes or the consumer ACK arrives, we could
still have some resilience against message loss with this in place.
Do you think that would be a useful option, or cause more problems than it
could solve?
Thanks,
Richard
> Improve performance of ConcurrentStoreAndDispatch
> -------------------------------------------------
>
> Key: AMQ-5077
> URL: https://issues.apache.org/jira/browse/AMQ-5077
> Project: ActiveMQ
> Issue Type: Wish
> Components: Message Store
> Affects Versions: 5.9.0
> Environment: 5.9.0.redhat-610343
> Reporter: Jason Shepherd
> Assignee: Gary Tully
> Attachments: Test combinations.xlsx, compDesPerf.tar.gz,
> topicRouting.zip
>
>
> We have publishers publishing to a topic which has 5 topic -> queue routings,
> and gets a max message rate attainable of ~833 messages/sec, with each
> message around 5k in size.
> To test this i set up a JMS config with topic queues:
> Topic
> TopicRouted.1
> ...
> TopicRouted.11
> Each topic has an increasing number of routings to queues, and a client is
> set up to subscribe to all the queues.
> Rough message rates:
> routings messages/sec
> 0 2500
> 1 1428
> 2 2000
> 3 1428
> 4 1111
> 5 833
> This occurs whether the broker config has producerFlowControl="false" set to
> true or false , and KahaDB disk synching is turned off. We also tried
> experimenting with concurrentStoreAndDispatch, but that didn't seem to help.
> LevelDB didn't give any notable performance improvement either.
> We also have asyncSend enabled on the producer, and have a requirement to use
> persistent messages. We have also experimented with sending messages in a
> transaction, but that hasn't really helped.
> It seems like producer throughput rate across all queue destinations, all
> connections and all publisher machines is limited by something on the broker,
> through a mechanism which is not producer flow control. I think the prime
> suspect is still contention on the index.
> We did some test with Yourkit profiler.
> Profiler was attached to broker at startup, allowed to run and then a topic
> publisher was started, routing to 5 queues.
> Profiler statistics were reset, the publisher allowed to run for 60 seconds,
> and then profiling snapshot was taken. During that time, ~9600 messages were
> logged as being sent for a rate of ~160/sec.
> This ties in roughly with the invocation counts recorded in the snapshot (i
> think) - ~43k calls.
> From what i can work out, in the snapshot (filtering everything but
> org.apache.activemq.store.kahadb),
> For the 60 second sample period,
> 24.8 seconds elapsed in
> org.apache.activemq.store.kahadb.KahaDbTransactionStore$1.removeAsyncMessage(ConnectionContext,
> MessageAck).
> 18.3 seconds elapsed in
> org.apache.activemq.store.kahadb.KahaDbTransactionStore$1.asyncAddQueueMessage(ConnectionContext,
> Message, boolean).
> From these, a further large portion of the time is spent inside
> MessageDatabase:
> org.apache.activemq.store.kahadb.MessageDatabase.process(KahaRemoveMessageCommand,
> Location) - 10 secs elapsed
> org.apache.activemq.store.kahadb.MessageDatabase.process(KahaAddMessageCommand,
> Location) - 8.5 secs elapsed.
> As both of these lock on indexLock.writeLock(), and both take place on the
> NIO transport threads, i think this accounts for at least some of the message
> throughput limits. As messages are added and removed from the index one by
> one, regardless of sync type settings, this adds a fair amount of overhead.
> While we're not synchronising on writes to disk, we are performing work on
> the NIO worker thread which can block on locks, and could account for the
> behaviour we've seen client side.
> To Reproduce:
> 1. Install a broker and use the attached configuration.
> 2. Use the 5.8.0 example ant script to consume from the queues,
> TopicQueueRouted.1 - 5. eg:
> ant consumer -Durl=tcp://localhost:61616 -Dsubject=TopicQueueRouted.1
> -Duser=admin -Dpassword=admin -Dmax=-1
> 3. Use the modified version of 5.8.0 example ant script (attached) to send
> messages to topics, TopicRouted.1 - 5, eg:
> ant producer
> -Durl='tcp://localhost:61616?jms.useAsyncSend=true&wireFormat.tightEncodingEnabled=false&keepAlive=true&wireFormat.maxInactivityDuration=60000&socketBufferSize=32768'
> -Dsubject=TopicRouted.1 -Duser=admin -Dpassword=admin -Dmax=1 -Dtopic=true
> -DsleepTime=0 -Dmax=10000 -DmessageSize=5000
> This modified version of the script prints the number of messages per second
> and prints it to the console.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
