asf | Simple , High performance PHP framework written in C | Caching library

You can use gregexpr and regmatches like:

You stumbled upon bug 64097: the comments in the META-INF/services/javax.el.ExpressionFactory file are not skipped, hence the strange error.

This issue was fixed in Tomcat version 8.5.51 and 9.0.31.

ActiveMQ Artemis has no default connection limit. I just wrote a quick test based on this which uses the Paho 1.2.5 MQTT client. It spun up 500 concurrent connections using both normal TCP and WebSockets. The test finished in less than 20 seconds with no errors. I'm just running this test on my laptop.

I noticed that your journal-buffer-timeout is 700000 which seems quite high which means you have a very low write speed of 1.43 writes per millisecond (i.e. a slow disk). The journal-buffer-timeout that is calculated, for example, on my laptop is 4000 which translates into a write-speed of 250 which is significantly faster than yours. My laptop is nothing special, but it does have an SSD. That said, SSDs are pretty common. If this low write-speed is indicative of the overall performance of your VM it may simply be too weak to handle the load you want. To be clear, this value isn't related directly to MQTT connections. It's just something I noticed while reviewing your configuration that may be indirect evidence of your issue.

The journal-buffer-timeout value is calculated and configured automatically when the instance is created. You can re-calculate this value later and configure it manually using the bin/artemis perf-journal command.

Ultimately, your issue looks environmental to me. I recommend you inspect your VM and network. TCP dumps may be useful to see perhaps how/why the connection is being reset. Thread dumps from the server during the time of the trouble would also be worth inspecting.

I know why this happened.

First, there's a built-in rule for GNU make that shows how to build a %.out file from a % file; make -p will show:

A segmentation fault happens when the code try to access a memory region that is not available.

Accessing an array out of bounds doesn't means that the memory before or after the area occupied by the array is not available: The compiler or the runtime usually put all varibales or data in general in a given block of memory. If your array is the last item of such a memory block, the accessing it with a to big index will produce a Segmentaion Fault but is the array is in the middle of the memory block, you will just access memory used for other data, giving unexpected result and undefined behavior.

If the array (In may example, but valid for anything) is written, accessing available memory will not produce a segmentation fault but will overwrite something else. It may produce unexpected results or crash or segmentation fault later! This kind of bug is frequently very difficult to find because the unexpected result/behavior looks completely independent of the root cause.

I have found out that the problem was caused by the entry: default_impersonation = airflow in my airflow config file. After removing it, the problem dissapeared.

First, it's important to note that there's no feature to make a client reconnect to the broker from which it disconnected after the client crashes/restarts. Generally speaking the client shouldn't really care about what broker it connects to; that's one of the main goals of horizontal scalability.

It's also worth noting that if the number of messages on the brokers and the number of connected clients is low enough that this condition arises frequently that almost certainly means you have too many brokers in your cluster.

That said, I believe the reason that your client isn't getting the messages it expects is because you're using the default redistribution-delay (i.e. -1) which means messages will not be redistributed to other nodes in the cluster. If you want to enable redistribution (which is seems like you do) then you should set it to >= 0, e.g.:

Tomcat is not reading your deployment descriptor c.xml. As you can see in the logs you have:

Unable to create directory for deployment: [/opt/tomcat/conf/Catalina/localhost]

Once you create the required directory /opt/tomcat/conf/Catalina/localhost and put your c.xml file in it, the starting logs will contain:

Deploying deployment descriptor [/opt/tomcat/conf/Catalina/localhost/c.xml]

instead of:

Deploying web application archive [/opt/tomcat/webapps/c.war]

and your valves should work.

Note - After creating xml file, change owner of both file and directory to tomcat user so that tomcat can deploy xml files

sudo chown tomcat:tomcat ${CATALINA_HOME}/conf/Catalina/localhost/ sudo chown tomcat:tomcat ${CATALINA_HOME}/conf/Catalina/localhost/ROOT.xml

You can map the json string to a tuple of the values that you want to extract: