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Date: Mon, 6 May 2013 11:15:24 +0530
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Subject: Re: Cached an already cached block (HBASE-5285)
From: ramkrishna vasudevan <ramkrishna.s.vasudevan@gmail.com>
To: user@hbase.apache.org
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Just to confirm you are getting this with LruBlockCache? If with
LruBlockCache then the issue is critical.
 Because we have faced similar issue with OffHeapCache.  But that is not
yet stable as far as i know.

Regards
Ram


On Mon, May 6, 2013 at 10:45 AM, Viral Bajaria <viral.bajaria@gmail.com>wrote:

> Hi,
>
> I have been consistently hitting the following error in one of my QA
> clusters. I came across two JIRAs, the first one (HBASE-3466) was closed
> saying "Cannot Reproduce" but a new one was re-opened under HBASE-5285.
>
> I am using HBase 0.94.4 and Hadoop 1.0.4
> 24 region servers (8 cores, 8GB RAM)
>
> In HBASE-5285, Ted Yu has commented that it could be due to a hash code
> collision. But if caching is enabled, wouldn't it return the block with
> which it's hash collides when we check the cache for block existence ? It
> should not even hit the code that tries to put into cache method unless and
> until there is some concurrency issue.
>
> Also HBASE-5285 states that it occurred during compaction for the reporter,
> but in my cluster I have disabled compaction, so this error happens with
> not just compaction.
>
> Let me know if you need any more information. I can volunteer to submit a
> patch if we can find the root cause.
>
> Thanks,
> Viral
>

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