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From Ryan Rawson <ryano...@gmail.com>
Subject Re: The hfile.block.cache.size = 0 performance is better than default(0.2) in random read? Is it possible?
Date Thu, 21 Oct 2010 06:20:31 GMT
block cache invalidation is done async and isnt done inline, so that
shouldn't be an issue.

could be related to GC... if you could produce and compare GC logs
that'd be helpful.

On Wed, Oct 20, 2010 at 11:18 PM, ChingShen <chingshenchen@gmail.com> wrote:
> Yes, only 14.7% :-(
>
> 2010-10-21 10:59:06,675 DEBUG
> org.apache.hadoop.hbase.io.hfile.LruBlockCache: Cache Stats: Sizes:
> Total=572.39557MB (600200272), Free=125.94194MB (132059696), Max=698.3375MB
> (732259968), Counts: Blocks=8992, Access=235641, Hit=34786, Miss=200855,
> Evictions=173, Evicted=191863, Ratios: *Hit  Ratio=14.762286841869354**%*,
> Miss Ratio=85.23771166801453%, Evicted/Run=1109.03466796875
>
> I agree much better performance with more cache, because that can improve
> the hit ratio in random read, but I want to know why I disabled block cache
> and got better throughput than default?
>
> 2010/10/21 Antonio Alvarado Hernández <aalvaradoh@gmail.com>
>
>> Hi all,
>> Could be related with a low hit ratio?
>> -aah
>>
>>
>

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