customized configuration of java heap size

[wyhhyw]

I'm using the docker neo4j as my graph database. However, when I make some Cypher queries, it always runs to "java heap space" error. And I tried to change the configure file under $neo4j/conf dir, which contains two files: neo4j.conf and neo4j-wrapper.conf. I changed the neo4j-wrapper.conf to enlarge the dbms.memory.heap.initial_size=2048 and dbms.memory.heap.max_size=4096. But when I start the container again, it was modified to the original one again. What can I do to make the memory size be larger?

[wyhhyw]

OK. I have found solutions here. However, even these official solutions, it seems useless when using --env=NEO4J_dbms_memory_heap_maxSize=4G. The values in conf files were changed again to 512M.

[benbc]

@WangAllen What does the command that you use to start the container look like?

[wyhhyw]

I ran the docker with this: docker run -d --name neo4j --publish=7474:7474 --volume=$HOME/neo4j/data:/data --env=NEO4J_dbms_memory_pagecache_size=2G --env=NEO4J_dbms_memory_heap_maxsize=4G neo4j. The container runs but the heap size is still 512M.

[benbc]

@WangAllen Thanks. It would be helpful if you could try again with a precise label rather than relying on latest; that way we have more chance of reproducing your problem.

[wyhhyw]

Yeah, I used the CE V3.0.6 version and the docker version is 1.6.2 on Ubuntu 15.04 (GNU/Linux 3.19.0-15-generic x86_64) platform.

[mbsimonovic]

How did you fix this? i'm having the same issue on ubuntu 16, docker 1.13, neo 2.3.7 community (neo4j 3.1.1 picks up these variables correctly):

$ docker run  -d -P --name neo --env=NEO4J_AUTH=none --env=NEO4J_dbms_memory_pagecache_size=1G --env=NEO4J_dbms_memory_heap_maxSize=2G  neo4j:2.3.7
$ docker exec -it neo bash -c 'ps axu | grep Xmx' 
root          1 80.1 11.2 3068368 323476 ?      Ssl  09:55   0:23 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java -cp /var/lib/neo4j/lib/ _<skip>_  slf4j-api-1.7.6.jar:/var/lib/neo4j/conf -server -XX:+DisableExplicitGC -Dorg.neo4j.server.properties=conf/neo4j-server.properties -Dlog4j.configuration=file:conf/log4j.properties -XX:+UseG1GC -XX:-OmitStackTraceInFastThrow -XX:hashCode=5 -Dneo4j.ext.udc.source=docker -Xms512m -Xmx512m -Dneo4j.home=/var/lib/neo4j -Dneo4j.instance=/var/lib/neo4j -Dfile.encoding=UTF-8 org.neo4j.server.CommunityBootstrapper

So despite --env=NEO4J_dbms_memory_heap_maxSize=2G, the server gets -Xmx512m. NEO4J_AUTH=none is however correctly applied.

[spacecowboy]

@mbsimonovic In 2.3 the environment variables are different:

https://github.com/neo4j/docker-neo4j/blob/master/src/2.3/docker-entrypoint.sh#L22

use NEO4J_CACHE_MEMORY and NEO4J_HEAP_MEMORY instead of NEO4J_dbms_memory_pagecache_size and NEO4J_dbms_memory_heap_maxSize

This described in the 2.3 manual: https://neo4j.com/developer/docker-23/

[mbsimonovic]

@spacecowboy thanks! Maybe the docs should be updated.

[hthetiot]

This does not work using latest or 3.0.
Works with 2.3 image version so far.

[EricGT]

With regards to

This does not work using latest or 3.0.

Currently running Neo4j Enterprise 3.4.6 via Docker on Windows 10 [Version 10.0.17134.228]

Have same problem where mounted config directory,
--volume=C:\Users\Eric\Documents/neo4j/conf:/conf with config file neo4j.conf is ignored.

However using command line options with docker run command to change config values works,
e.g. --env=NEO4J_dbms_memory_heap_initial__size=512m --env=NEO4J_dbms_memory_heap_max__size=2G

This can be verified in cypher-shell

neo4j> CALL dbms.listConfig("heap");

+----------------------------------------------------------------------------------------------------------------------------------+
| name                            | description                                                                           | value  |
+----------------------------------------------------------------------------------------------------------------------------------+
| "dbms.memory.heap.initial_size" | "Initial heap size. By default it is calculated based on available system resources." | "512m" |
| "dbms.memory.heap.max_size"     | "Maximum heap size. By default it is calculated based on available system resources." | "2G"   |
+----------------------------------------------------------------------------------------------------------------------------------+

2 rows available after 399 ms, consumed after another 5 ms

Note that while the command line argument names appear to be the same as in Configuration settings take care to read the Neo4j Operations Manual when using Docker; see section 2.5.3.1. Environment variables

Any configuration value (see Section A.1, “Configuration settings”) can be passed using the following naming scheme:
Prefix with NEO4J_.
Underscores must be written twice: _ is written as __.
Periods are converted to underscores: . is written as _.

It would be nice if these important notes were in more than one place, but then again when important notes are in several places, they do not always get updated consistently and then in the future when you find conflicting notes it can be harder to understand.