GC blocking application thread Neo4j 2.2 community version

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Amit Aggarwal

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Apr 18, 2014, 5:31:06 PM4/18/14
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Hello,

I am using neo4j 2.2 commmunity version on ubuntu 12.04 64bit 2 GB RAM 

I saw that after running neo4j for sometime , i got this

2013-07-09 12:19:51.933+0000 INFO  [org.neo4j]: GC Monitor: Application threads blocked for an additional 3406ms [total block time: 441.511s]
2013-07-09 12:20:17.351+0000 INFO  [org.neo4j]: GC Monitor: Application threads blocked for an additional 3143ms [total block time: 444.654s]
2013-07-09 12:20:20.654+0000 INFO  [org.neo4j]: GC Monitor: Application threads blocked for an additional 3202ms [total block time: 447.856s]
2013-07-09 12:20:24.281+0000 INFO  [org.neo4j]: GC Monitor: Application threads blocked for an additional 3527ms [total block time: 451.383s]
2013-07-09 12:20:27.954+0000 INFO  [org.neo4j]: GC Monitor: Application threads blocked for an additional 3573ms [total block time: 454.956s]
2013-07-09 12:20:31.193+0000 INFO  [org.neo4j]: GC Monitor: Application threads blocked for an additional 3139ms [total block time: 458.095s]

in message.log

Whats does it want ?? As of now db has only around 15500 nodes and around same number of relationships..
 

Here is my neo4j-wrapper.conf


wrapper.java.additional=-Dorg.neo4j.server.properties=conf/neo4j-server.properties
wrapper.java.additional=-Djava.util.logging.config.file=conf/logging.properties
wrapper.java.additional=-Dlog4j.configuration=file:conf/log4j.properties

#********************************************************************
# JVM Parameters
#********************************************************************

wrapper.java.additional=-XX:+UseConcMarkSweepGC
wrapper.java.additional=-XX:+CMSClassUnloadingEnabled

# Uncomment the following lines to enable garbage collection logging
#wrapper.java.additional=-Xloggc:data/log/neo4j-gc.log
#wrapper.java.additional=-XX:+PrintGCDetails
#wrapper.java.additional=-XX:+PrintGCDateStamps
#wrapper.java.additional=-XX:+PrintGCApplicationStoppedTime
#wrapper.java.additional=-XX:+PrintPromotionFailure
#wrapper.java.additional=-XX:+PrintTenuringDistribution

# Uncomment the following lines to enable JVM startup diagnostics
#wrapper.java.additional=-XX:+PrintFlagsFinal
#wrapper.java.additional=-XX:+PrintFlagsInitial

# Java Heap Size: by default the Java heap size is dynamically
# calculated based on available system resources.
# Uncomment these lines to set specific initial and maximum
# heap size in MB.
wrapper.java.initmemory=256
wrapper.java.maxmemory=1000

#********************************************************************
# Wrapper settings
#********************************************************************
# path is relative to the bin dir
wrapper.pidfile=../data/neo4j-server.pid

#********************************************************************
# Wrapper Windows NT/2000/XP Service Properties
#********************************************************************
# WARNING - Do not modify any of these properties when an application
#  using this configuration file has been installed as a service.
#  Please uninstall the service before modifying this section.  The
#  service can then be reinstalled.

# Name of the service

# User account to be used for linux installs. Will default to current
# user if not set.
wrapper.user=



Thanks
Amit Aggarwal 

Michael Hunger

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Apr 18, 2014, 6:00:30 PM4/18/14
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In general probably too little, RAM if you only have 2G in total as OS, FS-Caches and other services also take their share.

Depends also on what you're doing.

Perhaps you can share your graph.db/messages.log

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Amit Aggarwal

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Apr 19, 2014, 12:12:58 AM4/19/14
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Hello Micheal,

Please find attached messages.log.

PS : Can you please tell me why message.log is sooooo important. I tried looking in message.log but i donot find really helpful information.

How do you use message.log for resolving issues .

Thanks
messages.log

Amit Aggarwal

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Apr 21, 2014, 12:22:18 AM4/21/14
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Hello Michael,

I have upgraded my server to 4GB total RAM and I have allocated minimum 256 MB and maximum 2GB RAM to neo4j .
But still I got error and today it terminated by saying "JAVA Heap out of memory". moreover it is not exhausting complete 2 GB ram i saw it using HTOP.

I dun know why it is happening any suggestion please.

On Saturday, 19 April 2014 03:30:30 UTC+5:30, Michael Hunger wrote:

Jeferson dos Anjos

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May 20, 2015, 6:06:20 PM5/20/15
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I have the same problem. With no access to the database, the Neo4j is using 2GB of Ram and 43% processing. The calls come to take 20 seconds to respond.

I confess I'm getting very sad with Neo4j, there is always some performance problem and can not identify how to solve.

Did you ever solve this problem?

Hugs

Amit Aggarwal

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May 20, 2015, 10:43:39 PM5/20/15
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Hello there ,

Yes I resolved the problem. 
There was a problem with code for cypher execution. I will let you know exact details soon. 

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Amit Aggarwal

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May 21, 2015, 1:00:22 AM5/21/15
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Everytime I am executing cypher .. I was create ExeecutingEngine ..using 
ExecutionEngine executeEngine = new ExecutionEngine(graphDb);
    cypherEngine = executeEngine;


Micheal pointed out this error in my code. 
Now I create ExecutionEngine once and use to to execute all cyphers .. 



Thanks
Amit Aggarwal
Cofounder @ Revleg

Michael Hunger

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May 21, 2015, 4:37:23 AM5/21/15
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Perhaps you can share your code, domain, configuration etc.

Otherwise we can't help you.

What you've seeing can have many reasons but what you see is not normal behavior.

Michael
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