hama-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From 顾荣 <gurongwal...@gmail.com>
Subject Re: pagerank NullPointerException
Date Wed, 19 Sep 2012 07:32:21 GMT
Yeah, if you set the property in the site config, please remember to
restart your Hama to make the updated properties take effect.

If you only use this property for just once, I suggest you to modify the
code of PageRank example and recmpile it  to get it work as your purpose.
In this case, it's pretty easy, u just need add a line to set the
"hama.graph.
repair" be "true" in the driver part of the source code.


2012/9/19 Thomas Jungblut <thomas.jungblut@gmail.com>

> You can set this in the site config.
>
> 2012/9/19 Sandy Ding <sandy.dingxin@gmail.com>:
> > So I have to recompile the pagerank example?
> > Can I pass it as a parameter to the existing jar?
> >
> > 2012/9/19 Thomas Jungblut <thomas.jungblut@gmail.com>
> >
> >> Hey,
> >>
> >> if you read closely:
> >>
> >>
> http://wiki.apache.org/hama/WriteHamaGraphFile#Google_Web_dataset_.28local_mode.2C_pseudo_distributed_cluser.29
> >>
> >> You find that there is a property called "hama.graph.repair":
> >>
> >>     // hama takes care that the graph is complete
> >>     pageJob.set("hama.graph.repair", "true");
> >>
> >> This basically sends messages along the known edges and adds vertices
> >> if there aren't any on the "other side".
> >>
> >> If this isn't to scalable for you, then a preprocessing mapreduce job
> >> is fine, where you emit the vertex id as key along with the complete
> >> edge list as value, also the edge keys with an empty value.
> >> In the reducer you should get either multiple complete lines or empty
> >> values.
> >> In the case you get only an empty value, you know that this vertex
> >> wasn't included in the dataset and you can repair by emitting it in
> >> the reducer as single line.
> >>
> >>
> >> 2012/9/19 Sandy Ding <sandy.dingxin@gmail.com>:
> >> > Hi, guys,
> >> >
> >> > The web-google dataset seems to miss some key sites, for example,
> there
> >> is
> >> > no entry starting with 111067.
> >> > This leads to weird NullPointerException. How do you fix this?
> >> >
> >> > Cheers,
> >> > Sandy
> >>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message