Contribute to the DSpace Development Fund

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This page describes how to speed up execution of DSpace command-line scripts (class launcher) using Nailgun by Martian Software, Inc.

The reason why even the simplest DSpace command-line scripts usually take several seconds to run is because the Java class launcher has to create a new JVM instance every time it's run. Nailgun has a client/server architecture and implements a very lightweight JVM in the server part, which keeps running as a service and therefore doesn't have to be started up every time. You then use the command line nailgun client (ng) to connect to it to launch a class, which is considerably faster than starting up the JVM.

  1. Download and build the nailgun client and server (this assumes that dspace is installed in /dspace, that you have gcc installed and that you can run binaries from ~/bin):

    git clone git://
    cd nailgun
    mvn clean install
    cp nailgun-server/target/nailgun-server-0.9.2-SNAPSHOT.jar /dspace/lib/
    cp nailgun-server/target/nailgun-server-0.9.2-SNAPSHOT.jar /dspace/webapps/xmlui/WEB-INF/lib/
    cd nailgun-client
    gcc ng.c -o ng
    cp ng ~/bin
    # exit your shell and launch it again
  2. Start the nailgun server and add DSpace to its classpath:

    java -classpath /dspace/lib/nailgun-server-0.9.2-SNAPSHOT.jar com.martiansoftware.nailgun.NGServer &
    ng ng-cp /dspace/lib/*.jar /dspace/config
    ng ng-alias dspace
  3. Run the client:

    # instead of this:
    # use this:
    ng dspace
    # Example. Instead of 
    /dspace/bin/dspace update-discovery-index
    # use this
    ng dspace update-discovery-index
  4. After you're finished running multiple invocations of the DSpace command-line scripts, you can stop the Nailgun server:

    ng ng-stop


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  1. I see that Nailgun is in Maven Central now, so it should be possible to skip the manual copying of jar files, if one adds nailgun as a dependency to their pom.xml files. I don't know whether the DSpace project would accept such a proposal, but it would be a handy patch to have, I know I'd have no problems rolling it into my repository's codebase. 

  2. Borrowing from the installation instructions for the Replication Task Suite, I have added the following to my dspace-src/dspace/modules/additions/pom.xml file:

          <!-- Adding this dependency will install the nailgun server  --> 

    And that appears to work.