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From SuoNayi <>
Subject Re:Re: How to ensure LevelDB store uses a JNI driver
Date Thu, 07 Mar 2013 06:42:30 GMT
I have some confusions not answered until now:
1. A leveldb driver( pure java driver or the jni driver) seems like a jdbc driver, 
    it can not save the data without talking to the store engine(database).
    For the jni driver, does it will find the installed LevelDB on the broker at first?
    If not found what will behave next? Just use the experimental pure Java LevelDB  implement
    Can the pure jave driver talks to the the installed LevelDB?
    I download the source code from and issue 'make' command

    and install LevelDB.
2. How can I only enable jni driver for the LevelDB?
3. Does the jni driver performs faster than the purge java driver?
4. Is it production-ready for using LevelDB?

At 2013-03-06 23:36:20,"Christian Posta" <> wrote:
>Apollo does this. I think the logs are coming from the leveldb store, so
>when using with ActiveMQ 5.x it should be the same (but i didn't try yet).
>It will only log if NOT using the JNI impl.
>On Wed, Mar 6, 2013 at 12:35 AM, Claus Ibsen <> wrote:
>> On Wed, Mar 6, 2013 at 8:00 AM, SuoNayi <> wrote:
>> > Also I saw the leveldb-0.2.jar in the extra directory under the lib
>> directory, seems it's the java LevelDB implement.
>> >
>> > I removed the jar from the extra directory and deployed a new broker on
>> other new CentOS server and restarted the broker,
>> > but I could still send messages to the new broker and log files created
>> by LevelDB were present in the specific directory.
>> >
>> I think the leveldb driver/transport has a Java based driver that it
>> fallback and use if the JNI is not possible/present.
>> Though Hiram would be the best person to answer that.
>> And yeah if there is something we can make more obvious from INFO
>> logging when starting the broker which one is in use, that would be
>> great.
>> > So here I'm more confused about that the broker with removal the
>> leveldb-0.2.jar is deployed on the new CentOS server without
>> > LevelDB installation can still work.
>> > The version is activemq-5.7.0.fuse-71-047.
>> >
>> > At 2013-03-06 13:36:46,SuoNayi <> wrote:
>> >>Hi ,
>> >>Can we ensure LevelDB store uses a JNI driver or not via logging?
>> >>I have deployed brokers on two CentOS servers, one server with LevelDB
>> installation while the other without installation.
>> >>After changing the logging level to DEBUG, I still can not find logs to
>> indicate that a JNI driver or a pure java implement is used.
>> >>On the same server my broker was deployed without LevelDB installation
>> at first, I use a simple load producer to send massive
>> >>messages to measure performance,after that I installed LevelDB and
>> restarted the broker and the load producer.
>> >>What make me confused is that the performance measure is very close. So
>> I suspect if the JNI driver is used or not.
>> >>If not used the java LevelDB will be used?Can I assume the JNI driver
>> always performs better than the java driver?
>> >>
>> >>
>> >>Thanks,
>> >>SuoNayi
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>--
>> >>
>> >>Wangyin
>> >>
>> >>
>> --
>> Claus Ibsen
>> -----------------
>> Red Hat, Inc.
>> FuseSource is now part of Red Hat
>> Email:
>> Web:
>> Twitter: davsclaus
>> Blog:
>> Author of Camel in Action:
>*Christian Posta*
>twitter: @christianposta

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