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kandi X-RAY | OpenHFT Summary
kandi X-RAY | OpenHFT Summary
Review : The YourKit java profiler can help you optomize your java code, it displays a real-time display of CPU and memory usage. Another tab shows time spent in the garbage collector, how many collections have taken place recently. You can force a garbage collection to take place to watch the effect on performance. Other tabs provide info on the number of running threads and the number of classes loaded. YourKit also allows you to take a snapshot of the running process; this is automatically saved and can be subsequently reopened for comparative purposes. Within the snapshot, you can view a hotspot listing, showing the methods where the application spent most of its time. You can also see a call tree - either merged or arranged by individual thread - and view back traces of individual methods showing where they were called from.
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Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of OpenHFT
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Trending Discussions on OpenHFT
QUESTION
I'm currently trying to marshal a certain POJO as JSON and write it to an output queue. This is the run down of what I'm trying to do:
...ANSWER
Answered 2022-Mar-29 at 07:38The WireType here is the format used by the Queue itself, and the queue uses features JSON/TextWire doesn't support such as thread-safe 128-bit values.
There isn't an elegant way of writing JSON into the queue, however, you don't need to. You can convert it to JSON when you read it instead should you need, however in this example you don't as you are also using a method reader.
QUESTION
I have upgraded my Java EE application to JDK 11 from JDK 8. But when I'm deploying into the JBOSS EAP 7.3 server I get the following exception.
...ANSWER
Answered 2022-Jan-24 at 05:46Your code should use java.lang.ref.Cleaner instead of jdk.internal.ref.Cleaner. The latter was removed in Java 9:
If the usage of the "internal" Cleaner class is actually coming from 3rd-party library code, then you need to upgrade the library to a Java 11 compatible version.
QUESTION
this is the version of Chronicle Queue:
...ANSWER
Answered 2021-Nov-18 at 08:28try the following: you can find the documentation in https://github.com/OpenHFT/Chronicle-Queue
QUESTION
I am experimenting with ChronicleWire. As described in features optional fields are supported out of the box.
I just created a simple self-describing entity with one optional (nullable) field:
...ANSWER
Answered 2021-Oct-21 at 09:27As SelfDescribingMarshallable is BytesMarsahallable, Map prefers to use this lower level serialization. However, because it is so low level, it doesn't support null values.
You can tell the builder to use Marshallable by setting the valueMarshaller
QUESTION
I have an application using Boot Strap running with cassandra 4.0, Cassandra java drive 4.11.1, spark 3.1.1 into ubuntu 20.4 with jdk 8_292 and python 3.6.
When I run a function that it call CQL by spark, the tomcat gave me the error bellow.
Stack trace:
...ANSWER
Answered 2021-May-25 at 23:23I openned two JIRA to understand this problem. See the links below:
QUESTION
One of our system has a micro service architecture using Apache Kafka as a service bus. Low latency is a very important factor but reliability and consistency (exactly once) are even more important.
When we perform some load tests we noticed signifiant performance degradation and all investigations pointed to big increases in Kafka topics producer and consumer latencies. No matter how much configuration we changed or more resources we added we could not get rid of the symptoms.
At the moment our needs are processing 10 transactions per second (TPS) and the load test is exercising 20 TPS but as the system is evolving and adding more functionality we know we'll reach a stage when the need will be 500TPS so we started being worried if we can achieve this with Kafka.
As a proof of concept I tried to switch to one of our micro services to use a chronicle-queue instead of a Kafka topic. It was easy to migrate following the avro example as from Chronicle-Queue-Demo git hub repo
...ANSWER
Answered 2021-Apr-20 at 01:55Hand building the Avro object each time seems a bit of a code smell to me.
Can you create a predefined message -> avro serializer and use that to feed the queue?
Or, just for testing, create one avro object outside the loop and feed that one object into the queue many times. That way you can see if it is the building or the queuing which is the bottleneck.
More general advice:
Maybe attach a profiler and see if you are making an excessive amount of object allocations. Which is particularly bad if they are getting promoted to higher generations.
See if they are your objects or Chronicle Queue ones.
Is your code maxing out your ram or cpu (or network)?
QUESTION
I need to serialize a list of SelfDescribingMarshallables of the same type as CSV output row by row using Chronicle Wire. But net.openhft.chronicle.wire.WireType#CSV produces a row for every object field, so it is not a CSV.
Are there any code samples?
ANSWER
Answered 2020-Dec-17 at 12:25WireType#CSV is currently not in a working condition unfortunately as we haven't had any incentive to support it.
However it's still possible to use low-level CSV marshalling via BytesMarshallable (not SelfDescribingMarshallable), see example here
QUESTION
Hello I am trying to send http request using low level library chronicle wire. I was able to get this working with use of java sockets but I am curious about the diff with use of this lib. Bellow the calling code:
...ANSWER
Answered 2020-Dec-03 at 15:26While I am sure you could get this to work, it isn't a natural choice to use with HTTP.
However, if this is just an exercise, you should avoid writingDocument as this prepends a 32-bit length before the content which HTTP doesn't expect.
The createServerSocketChannelFor method is for generating a dummy server for testing purposes so it would prevent you from contacting the server you have in mind.
I suggest you get this working with a library designed for HTTP such as the one built into Java.
QUESTION
We had a StreamCorruptedException from chroniclequeue(chronicle-queue-5.20.106, Red Hat Linux release 6.10) and we have pasted the stacktrace below. During that time, there was a very high IO/disk operation by completely different process which we believe caused the chroniclequeue to pause for more than 15seconds and caused this corruption.
Even after restart as the queue was corrupted and it couldn't come up. Only way is to delete and start fresh, meaning loosing millions of data
Please help with solution or any work around. Thanks
STACKTRACE
...ANSWER
Answered 2020-Nov-19 at 15:23If there's a possibility for your application to be stalled for 15 seconds there's no solution possible on the Chronicle Queue side - you should reconsider the way your software works as Chronicle's tools are developed with ultra-low-latency in mind and we cater for microsecond latencies, not seconds.
If the lock is forcibly unlocked which is the case here the data WILL be corrupted irreversibly.
A workaround however could be to increase the timeout - default is 15000ms but when creating a queue you can increase it by using builder#timeoutMS() to specify something that works in your environment.
QUESTION
I am interested in low-latency code and that`s why I tried to configure thread affinity. In particular, it was supposed to help to avoid context switches.
I have configured thread affinity using https://github.com/OpenHFT/Java-Thread-Affinity. I run very simple test code that just spins in a cycle checking a time condition.
...ANSWER
Answered 2020-Oct-18 at 22:42A voluntary context switch usually means a thread is waiting for something, e.g. for a lock to become free.
async-profiler can help to find where context switches happen. Here is a command line I used:
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