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From lewis john mcgibbney <lewis.mcgibb...@gmail.com>
Subject Re: Gora CassandraStore is not thread safe?
Date Mon, 29 Aug 2011 20:41:25 GMT
Hi Tom,

Apologies for cross posting, this would not usually be the case but I'm
hoping that if any results come from the thread then both communities can
benefit.

I'm in the process of getting Cassandra 0.8.4 working with Nutch 2.0 and
Gora 0.2 myself and seem to be having some nasty problems.

Some questions for you

1) How are you running Nutch local or deploy?
2) How are you running Cassandra, local or deployed in a cluster?

The obvious thoughts are that this is a bug and that there are
method(s)/object(s) which are not safe.

Have you gotten any further with this?

Lewis


On Wed, Aug 10, 2011 at 8:43 PM, Tom Davidson <tdavidson@covario.com> wrote:

> Has anyone tested the CassandraStore in gora 0.2 using multiple threads?
>  The nutch 2 fetcher architecture has many threads writing to one
> GoraRecordWriter and I am getting concurrent modification errors like below.
>
> Caused by: java.util.ConcurrentModificationException
>               at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
>               at java.util.HashMap$KeyIterator.next(HashMap.java:828)
>               at
> org.apache.gora.cassandra.store.CassandraStore.flush(CassandraStore.java:192)
>               at
> org.apache.gora.mapreduce.GoraRecordWriter.write(GoraRecordWriter.java:65)
>
>
>
>
>
>


-- 
*Lewis*

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