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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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