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From 顾荣 <gurongwal...@gmail.com>
Subject Re: Question about the "peer.getPeerIndex()" API in Hama
Date Wed, 19 Sep 2012 01:10:36 GMT
Hi,

BTW, is there a java user API doc for Hama?

Regards,
Walker

2012/9/19 顾荣 <gurongwalker@gmail.com>

> Okay, I got it ,thanks.
>
>
> 2012/9/19 Suraj Menon <surajsmenon@apache.org>
>
>> Hi Walker,
>>
>> The old contract was changed because if a task gets re-allocated on a
>> different machine on failure, that can change the peer-Ids of all the
>> tasks.
>> The current trunk version returns the task-id, which remains same
>> throughout the lifecycle of the job execution.
>> With this peerIndex could be made a part of your computation logic.
>>
>> -Suraj
>>
>> On Tue, Sep 18, 2012 at 11:59 AM, Thomas Jungblut <
>> thomas.jungblut@gmail.com
>> > wrote:
>>
>> > Hi Walker,
>> >
>> > seems the contract is broken and the array is not sorted anymore.
>> >
>> > Try to use:
>> >
>> > String[] names = peer.getAllPeerNames();
>> > Arrays.sort(names);
>> > int index = Arrays.binarySearch(names, peer.getPeerName());
>> >
>> > Sorry for the inconvenience, we have replaced it with the task id in
>> > the latest trunk, so this will be fixed in the next release.
>> >
>> > 2012/9/18 顾荣 <gurongwalker@gmail.com>:
>> > > Hi,
>> > >
>> > > I have a Hama cluster of 3 nodes. The host name of the nodes are
>> > slave019,
>> > > slave020, slave021. I wirte a simple program to test the PeerIndex and
>> > > PeerName info in Hama.
>> > >
>> > > In setup function, I choose a peer as master, and the in bsp function
>> > each
>> > > peer get its PeerIndex and its PeerName by peer.getPeerIndex() and
>> > > peer.getPeerName()  API and send it to the master peer. Lastly, in
>> > cleanup
>> > > function of the master peer, it write out the messages in its queue.
>> The
>> > > result is below:
>> > >
>> > >     peerName: slave020:61001    peerIndex: -7
>> > >     peerName: slave019:61002    peerIndex: 4
>> > >     peerName: slave021:61001    peerIndex: 6
>> > >     peerName: slave019:61001    peerIndex: -1
>> > >     peerName: slave021:61002    peerIndex: -8
>> > >     peerName: slave020:61002    peerIndex: -7
>> > >     peerName: slave019:61003    peerIndex: 5
>> > >     peerName: slave021:61003    peerIndex: 7
>> > >     peerName: slave020:61003    peerIndex: -7
>> > >
>> > > The peerNames are reasonable, but I am confused with the peerIndex
>> > > information. What does they mean? According to the source code of
>> > > BSPPeer.java, the comment message is below
>> > >    /**
>> > >    * @return the index of this peer from sorted array by name.
>> > >    */
>> > >   public int getPeerIndex();
>> > >
>> > > However, the peerIndex messages I got seem not to be so....Can you
>> give
>> > me
>> > > a hint?
>> > >
>> > > Thanks in advance.
>> > >
>> > > Walker
>> >
>>
>
>

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