my nodejs process which was running at Linux, now it is hang and the CPU is 100%. Is there anyway I can do to debug it and find the reason? Do I need to collect dump and how? Thanks.
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Maybe this will be useful https://www.joyent.com/blog/mdb-and-node-js – raidendev Jul 24 '14 at 07:21
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1Have a look at http://stackoverflow.com/questions/1911015/how-to-debug-node-js-applications/16512303#16512303 – Matt Harrison Jul 24 '14 at 07:21
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Plus you can always run `strace` – Nitzan Shaked Jul 24 '14 at 07:30
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@raidendev Can MDB be used in CentOS? – kevin_song Jul 24 '14 at 08:35
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Should be, try `yum install mdbtools` – raidendev Jul 24 '14 at 08:37
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@raidendev that's a different package, it contains tools for working with MS Access databases – maccam94 Apr 23 '19 at 05:48
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There's an npm module called why-is-node-running that can give you info like:
There are 4 known handle(s) keeping the process running and 0 unknown
Known handles:
# Timer
/Users/maf/dev/node_modules/why-is-node-running/example.js:6 - setInterval(function () {}, 1000)
/Users/maf/dev/node_modules/why-is-node-running/example.js:10 - createServer()
# TCP
/Users/maf/dev/node_modules/why-is-node-running/example.js:7 - server.listen(0)
/Users/maf/dev/node_modules/why-is-node-running/example.js:10 - createServer()
# TCP
/Users/maf/dev/node_modules/why-is-node-running/example.js:7 - server.listen(0)
/Users/maf/dev/node_modules/why-is-node-running/example.js:11 - createServer()
# Timer
/Users/maf/dev/node_modules/why-is-node-running/example.js:13 - setTimeout(function () {
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Excellent! Now I know what's in the way. This is exactly what I was looking for. – Alexis Wilke Nov 28 '18 at 18:03
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This tool helps with processes which have completed their work but not exited the vm. It does not help with infinite loops, which is what this question is about. – Rich May 23 '22 at 14:49
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For me the why-is-node-running package was not very useful since I had an infinite while loop.
I wish there was a tool that will detect infinite loop all around the project.
What solve for me the issue was to manually reverse some versions of my project and to manually re-add the code I deleted, until I found out what cause my application to hangs, as I said, a infinite while loop.
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1Why there's no tool to detect infinite loops: https://en.wikipedia.org/wiki/Halting_problem I know this is old, but just posting because it's kinda interesting. – Sam DeSota Feb 02 '23 at 20:13