I upgraded to Community version 3.0 and now when I open my database the CPU stays consistently above 85%. I've tried uninstalling and reinstalling, deleting the old installs and their config files and reinstalling, and letting it run in case neo4j was reindexing or similar and just needed time. The database was running very well under 3.0.0-M02 but I don't have that exe to try reinstalling that. I've tried 3.0.0-M05 which didn't help.
Can anyone suggest a way for me to get the database running properly again?
Is it doing recovery? If you start the database, does it fully start as expected and then go into this "mode"? Can you do a thread dump and paste here? For capturing a thread dump use jps -lm to figure out which process ID your neo4j process has and capture the thread dump using jstack <pid>, e.g. jstack 15432 > myfile.txt
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I downloaded neo4j 3.4.0 Community edition on Ubuntu 16.04 and installed it.
I launched it successfully once with command ./neo4j console
But after I restarted the system, I used the same command ./neo4j console in /bin/, there is an error: could not find or load main class org.neo4j.server.CommunityEntryPoint
Anyone knows how to solve it?
the neo4j have been based on java. please check jdk path in env.
After trying many things (and no success).
I reinstalled the app by deleting ~/.configs/Neo4j-desktop and running again the Appimage file.
consider by this action you will lose license-key (and if you use Appimage version also all Db-data) so backup first if you have important data.
I'm running Neo4j 3.2.6 on CENTOS 6.9. I have two problems:
First, Neo4j keeps stopping (typically about 5 times per day). There is nothing in the debug.log at the time of the failure (although there are many lines from the time I restart the service). How can I identify the problem? Which log files would give me a clue to the problem? Happy to share log files here if someone tells me which files to share.
Second, the above problem is compounded by the fact that I can't get Neo4j to restart automatically when it fails. I believe CENTOS 6.9 uses Upstart but I'm not having much luck setting this up. How do I set up Neo4j to restart on failure in CENTOS 6.9?
Neo4J enterprise is hanging indefinitely. Recovery requires a Neo4J restart. We use Python scripts with py2neo to ingest public data into Neo4J enterprise 3.0.4. So far we have been unable to complete the ingestion script. Before the script completes, Neo4J hangs indefinitely. There is nothing interesting in the logs. If we try the browser, the busy cursor appears and spins. This problem started for us when we upgraded from 3.0.2 to 3.0.4.
Has anyone else encountered this problem? For now, we'll try reverting the Neo4J release and see if that fixes the problem.
I am using Neo4j version 1.8.1.
When I stopped the Neo4j service and started it up again, it will not respond at all.
I am unable to connect to the database using the Neo4j browser even though the service is running.
Any ideas/suggestions on how to troubleshoot this issue? It was working fine until I restarted the service.
Thanks
If you log Java's garbage collection to a file, you can tail this file to get a clue how busy neo4j is during startup, especially, as pointed out, following an unclean shutdown.
The Java startup option you need is:
-Xloggc:neo4j-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps
I'm having ruby instances from mod_rails go "rogue" -- these processes are no longer listed in passenger-status and utilize 100% cpu.
Other than installing god/monit to kill the instance, can anyone give me some advice on how to prevent this? I haven't been able to find anything in the logs that helps.
If you're using Linux, you can install the "strace" utility to see what the Ruby process is doing that's consuming all the CPU. That will give you a good low-level view. It should be available in your package manager. Then you can:
$ sudo strace -p 22710
Process 22710 attached - interrupt to quit
...lots of stuff...
(press Ctrl+C)
Then, if you want to stop the process in the middle and dump a stack trace, you can follow the guide on using GDB in Ruby at http://eigenclass.org/hiki.rb?ruby+live+process+introspection, specifically doing:
gdb --pid=(ruby process)
session-ruby
stdout_redirect
(in other terminal) tail -f /tmp/ruby_debug.(pid)
eval "caller"
You can also use the ruby-debug Gem to remotely connect to debug sockets you open up, described in http://duckpunching.com/passenger-mod_rails-for-development-now-with-debugger
There also seems to be a project on Github concerned with debugging Passenger instances that looks interesting, but the documentation is lacking:
http://github.com/ddollar/socket-debugger/tree/master
I had a ruby process related to Phusion Passenger, which consumed lots of CPU, even though it should have been idle.
The problem went away after I ran
date -s "`date`"
as suggested in this thread. (That was on Debian Squeeze)
Apparently, the problem was related to a leap second, and could affect many other applications like MySQL, Java, etc. More info in this thread on lklm.
We saw something similar to this with very long running SQL queries.
MySQL would kill the queries because they exceeded the long running limit and the thread never realized that the query was dead.
You may want to check the database logs.
This is a recurring issue with passenger. I've seen this problem many times helping people that ran ruby on rails with passenger. I don't have a fix but you might want to try this http://www.modrails.com/documentation/Users%20guide%20Apache.html#debugging_frozen