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From "John Vines (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-3349) LruBlockCache is miscalculating sizes
Date Thu, 20 Nov 2014 18:04:33 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-3349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14219679#comment-14219679
] 

John Vines commented on ACCUMULO-3349:
--------------------------------------

Doing a code inspection, it looks like LruBlockCache.cacheBlock has no synchronization or
other logic to handle concurrent requests to cache the same block (unless this is somehow
handled higher in the code, but I'm doubtful).

> LruBlockCache is miscalculating sizes
> -------------------------------------
>
>                 Key: ACCUMULO-3349
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3349
>             Project: Accumulo
>          Issue Type: Bug
>    Affects Versions: 1.6.0
>            Reporter: John Vines
>
> On a system, we have index configured to 512MB and data block caches set to 1GB. I'm
seeing the total size seemingly horrendously miscalculated, resulting in a LOT of eviction
calls.
> {code}2014-11-17 22:07:54,814 [cache.LruBlockCache] DEBUG: Block cache LRU eviction started.
 Attempting to free 58954734976 bytes
> 2014-11-17 22:07:54,817 [cache.LruBlockCache] DEBUG: Block cache LRU eviction completed.
Freed 102696 bytes.  Priority Sizes: Single=186.14093MB (195182912), Multi=384.03125MB (402685944),Memory=0.0MB
(0)
> 2014-11-17 22:07:54,820 [cache.LruBlockCache] DEBUG: Block cache LRU eviction started.
 Attempting to free 58954734976 bytes
> 2014-11-17 22:07:54,823 [cache.LruBlockCache] DEBUG: Block cache LRU eviction completed.
Freed 102680 bytes.  Priority Sizes: Single=186.14093MB (195182920), Multi=384.03125MB (402685936),Memory=0.0MB
(0)
> 2014-11-17 22:07:54,829 [cache.LruBlockCache] DEBUG: Block cache LRU eviction started.
 Attempting to free 58954734984 bytes
> 2014-11-17 22:07:54,832 [cache.LruBlockCache] DEBUG: Block cache LRU eviction completed.
Freed 205384 bytes.  Priority Sizes: Single=186.043MB (195080224), Multi=384.12918MB (402788640),Memory=0.0MB
(0)
> {code}
> {code}2014-11-17 22:06:39,439 [cache.LruBlockCache] DEBUG: Cache Stats: Sizes: Total=56991.715MB
(59760144624), Free=-55967.715MB (-58686402800), Max=1024.0MB
>  (1073741824), Counts: Blocks=581902, Access=261753272, Hit=202812039, Miss=58941233,
Evictions=45047347, Evicted=53777417, Ratios: Hit Ratio=77.4821341
> 0377502%, Miss Ratio=22.51785844564438%, Evicted/Run=1.1937975883483887, Duplicate Reads=4581914
> 2014-11-17 22:07:39,419 [cache.LruBlockCache] DEBUG: Cache Stats: Sizes: Total=835.4461MB
(876028744), Free=-323.4461MB (-339157832), Max=512.0MB (536870912), Counts: Blocks=19881,
Access=171866619, Hit=171174512, Miss=692107, Evictions=300619, Evicted=595529, Ratios: Hit
Ratio=99.5972990989685%, Miss Ratio=0.402700062841177%, Evicted/Run=1.9810091257095337, Duplicate
Reads=76697
> 2014-11-17 22:07:39,439 [cache.LruBlockCache] DEBUG: Cache Stats: Sizes: Total=56991.418MB
(59759831656), Free=-55967.418MB (-58686089832), Max=1024.0MB (1073741824), Counts: Blocks=581901,
Access=261755962, Hit=202813386, Miss=58942576, Evictions=45048521, Evicted=53778759, Ratios:
Hit Ratio=77.48185992240906%, Miss Ratio=22.518140077590942%, Evicted/Run=1.1937963962554932,
Duplicate Reads=4581916
> 2014-11-17 22:08:39,419 [cache.LruBlockCache] DEBUG: Cache Stats: Sizes: Total=835.1727MB
(875742096), Free=-323.17273MB (-338871184), Max=512.0MB (536870912), Counts: Blocks=19762,
Access=171879228, Hit=171187080, Miss=692148, Evictions=300642, Evicted=595689, Ratios: Hit
Ratio=99.5972990989685%, Miss Ratio=0.40269438177347183%, Evicted/Run=1.9813898801803589,
Duplicate Reads=76697
> {code}
> Currently do not have log history to pinpoint where/where/if there was a slow incline
to get to 55GB or if it was spontaneous at some discernible point.



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