Hi there, see inline for my take to answering your questions. If someone has more info please share and/or correct.
On Sun, Aug 21, 2011 at 10:39 AM, mike_t <t.pr...@gmx.net> wrote: > I installed neo4j as a service on linux. Then I configured in the > neo4j-community-1.4.1/conf/neo4j-wrapper.conf file following init and max > memory: > > # Initial Java Heap Size (in MB) > wrapper.java.initmemory=512 > > # Maximum Java Heap Size (in MB) > wrapper.java.maxmemory=768 > > The "top" output shows following: > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 17408 neo4j 18 0 1188m 155m 11m S 0 5.1 2:12.76 java > > > Should neo4j not reserverd 512m memory? What did I wrong? Asking for any amount of memory does not mean that the memory pages are actually allocated - they are reserved. The JVM marks a range of addresses as reserved and the OS obliges, but through the way virtual memory works, the RAM is not actually used. This means that the JVM "thinks" that it has 512M but the OS knows better. The upside of not needing to do re-sizing calculations on heap growth is still there - when the JVM decides to write to a reserved page that is not still allocated, a page fault will be raised, the kernel will intervene etc, as per usual. > How can I discover If neo4j is running in java server mode? Result of "java > -version" is: > OpenJDK 64-Bit Server VM (build 19.0-b09, mixed mode). Interesting question. It seems there is no vendor independent way - the client vs server thing is vendor dependent to begin with. The closest thing that seems to work is parsing the VM name string, reachable via System.getProperty( "java.vm.name" ) which on my machine returns Java HotSpot(TM) 64-Bit Server VM with java -version printing java version "1.6.0_24" Java(TM) SE Runtime Environment (build 1.6.0_24-b07) Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02, mixed mode) The same is reported of course via jconsole. Interestingly, i could not start a client JVM. The JRE's help text talks about a -server option only and that the default is server. No -client, although the JVM starts with it in the command line. I guess this has to do with all my machines being 64-bit multicore. Hope the above helped. cheers, CG > -- > View this message in context: > http://neo4j-community-discussions.438527.n3.nabble.com/Neo4j-Rest-Server-memory-configuration-tp3272360p3272360.html > Sent from the Neo4j Community Discussions mailing list archive at Nabble.com. > _______________________________________________ > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > _______________________________________________ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user