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Posted to issues@hbase.apache.org by "stack (JIRA)" <ji...@apache.org> on 2018/03/01 20:06:00 UTC

[jira] [Commented] (HBASE-17819) Reduce the heap overhead for BucketCache

    [ https://issues.apache.org/jira/browse/HBASE-17819?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16382565#comment-16382565 ] 

stack commented on HBASE-17819:
-------------------------------

Where are we w/ this [~anoop.hbase] sir?

> Reduce the heap overhead for BucketCache
> ----------------------------------------
>
>                 Key: HBASE-17819
>                 URL: https://issues.apache.org/jira/browse/HBASE-17819
>             Project: HBase
>          Issue Type: Sub-task
>          Components: BucketCache
>            Reporter: Anoop Sam John
>            Assignee: Anoop Sam John
>            Priority: Major
>             Fix For: 2.0.0
>
>         Attachments: HBASE-17819_V1.patch, HBASE-17819_V2.patch, HBASE-17819_V3.patch
>
>
> We keep Bucket entry map in BucketCache.  Below is the math for heapSize for the key , value into this map.
> BlockCacheKey
> ---------------
> String hfileName  -  Ref  - 4
> long offset  - 8
> BlockType blockType  - Ref  - 4
> boolean isPrimaryReplicaBlock  - 1
> Total  =  12 (Object) + 17 = 29
> BucketEntry
> ------------
> int offsetBase  -  4
> int length  - 4
> byte offset1  -  1
> byte deserialiserIndex  -  1
> long accessCounter  -  8
> BlockPriority priority  - Ref  - 4
> volatile boolean markedForEvict  -  1
> AtomicInteger refCount  -  16 + 4
> long cachedTime  -  8
> Total = 12 (Object) + 51 = 63
> ConcurrentHashMap Map.Entry  -  40
> blocksByHFile ConcurrentSkipListSet Entry  -  40
> Total = 29 + 63 + 80 = 172
> For 10 million blocks we will end up having 1.6GB of heap size.  
> This jira aims to reduce this as much as possible



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