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I believe there are few runtimes out there that have such a good monitoring and profiling tools for free and out of the box as Java. Java Flight Recorder, remot

by miskin 6y ago

I believe there are few runtimes out there that have such a good monitoring and profiling tools for free and out of the box as Java. Java Flight Recorder, remote debugging and monitoring can be really useful for rare production performance issues.

lostcolony 6y ago
It's funny you should mention that in response to a post talking about Erlang. :P Because, yes, there are few. The BEAM happens to be one that definitely beats the JVM on that front.
- The_rationalist 6y ago
  In which précise aspect does it outperform jvm tooling?
  - lostcolony 6y ago
    So monitoring and profiling are pretty similar in what sort of things they tell you, but the meaningfulness tends to feel higher due to the programming model. Here's a fairly recent blog post giving an example from someone trying the BEAM for the first time, coming from the JVM - https://medium.com/@mrjoelkemp/jvm-struggles-and-the-beam-4d9c58547410 https://medium.com/@mrjoelkemp/jvm-struggles-and-the-beam-4d... But when it comes to remote debugging, and more specifically, a general "I want to understand what is happening in production", the ability to attach a REPL, alongside your tools, is amazing. I can insert a breakpoint, sure (if I for some reason built my production instance with debug info), but just as easily (without any debug info compiled in!), and more usefully, I can query actor state, mailboxes, etc, fire a message to a process to see what happens, etc...all the things you'd get with a REPL running locally in your dev environment, basically. Do stuff like query for internal state for a process, then call a function with it to see what happens to the data, all in isolation from the normal execution flow (since immutable data gives you a degree of safety to actually run that live code, with copies of the live data, and see what happens). I can even remotely load new code, if I want, effectively allowing me to deploy a hotfix without taking the node down. And I can do all of this in prod. All of this is, of course, super dangerous, but with great power etc etc.

by miskin 6y ago

lostcolony 6y ago

It's funny you should mention that in response to a post talking about Erlang. :P Because, yes, there are few. The BEAM happens to be one that definitely beats the JVM on that front.

The_rationalist 6y ago
In which précise aspect does it outperform jvm tooling?
- lostcolony 6y ago
  So monitoring and profiling are pretty similar in what sort of things they tell you, but the meaningfulness tends to feel higher due to the programming model. Here's a fairly recent blog post giving an example from someone trying the BEAM for the first time, coming from the JVM - https://medium.com/@mrjoelkemp/jvm-struggles-and-the-beam-4d9c58547410 https://medium.com/@mrjoelkemp/jvm-struggles-and-the-beam-4d... But when it comes to remote debugging, and more specifically, a general "I want to understand what is happening in production", the ability to attach a REPL, alongside your tools, is amazing. I can insert a breakpoint, sure (if I for some reason built my production instance with debug info), but just as easily (without any debug info compiled in!), and more usefully, I can query actor state, mailboxes, etc, fire a message to a process to see what happens, etc...all the things you'd get with a REPL running locally in your dev environment, basically. Do stuff like query for internal state for a process, then call a function with it to see what happens to the data, all in isolation from the normal execution flow (since immutable data gives you a degree of safety to actually run that live code, with copies of the live data, and see what happens). I can even remotely load new code, if I want, effectively allowing me to deploy a hotfix without taking the node down. And I can do all of this in prod. All of this is, of course, super dangerous, but with great power etc etc.