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From Nicolas Spiegelberg <nspiegelb...@fb.com>
Subject Re: LIRS cache as an alternative to LRU cache
Date Tue, 21 Feb 2012 17:19:55 GMT

You're correct.  The existing algorithm is called an Adaptive Replacement
Cache.  However, note that this cache does need some proper tuning for
optimal efficiency.


On 2/21/12 12:09 PM, "Vladimir Rodionov" <vrodionov@carrieriq.com> wrote:

>afaik, existing LruBlockCache is not exactly LRU cache
>It utilizes more advanced algorithm to avoid cache trashing during scan
>ops by
>dividing cache into three sub-caches (for newly added blocks, for
>promoted blocks and for in-memory blocks)
>Best regards,
>Vladimir Rodionov
>Principal Platform Engineer
>Carrier IQ, www.carrieriq.com
>e-mail: vrodionov@carrieriq.com
>From: Nicolas Spiegelberg [nspiegelberg@fb.com]
>Sent: Tuesday, February 21, 2012 9:01 AM
>To: dev@hbase.apache.org
>Subject: Re: LIRS cache as an alternative to LRU cache
>We had the author of LIRS come to Facebook last year to talk about his
>algorithm and general benefits.  At the time, we were looking at
>increasing block cache efficiency.  The general consensus was that it
>wasn't an exponential perf gain, so we could get bigger wins from
>cache-on-write intelligence, in-memory data compression techniques, and
>adding stats so we could understand how to tune the existing LRU
>algorithm.  I still think that these 3 goals are more important at the
>moment because LIRS would be a decent bit of code and only incremental
>gain.  It's probably something to revisit in a year or two.
>On 2/21/12 8:26 AM, "yuzhihong@gmail.com" <yuzhihong@gmail.com> wrote:
>>Shall we experiment with low inter-reference recency set replacement
>>policy to see if block cache becomes more effective ?
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