[jira] [Commented] (HBASE-7404) Bucket Cache:A solution about CMS,Heap Fragment and Big Cache on HBASE

["Ted Yu (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-7404?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13541645#comment-13541645 ] 

Ted Yu commented on HBASE-7404:
-------------------------------

For patch v9, I got the following compilation error:
{code}
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.5.1:testCompile (default-testCompile) on project hbase-server: Compilation failure
[ERROR] /Users/tyu/trunk/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java:[303,30] illegal forward reference
{code}
I think this is due to deserializerIdentifier being referenced in the CacheableDeserializer:
{code}
   private static final CacheableDeserializer<Cacheable> blockDeserializer =
...
+        @Override
+        public int getDeserialiserIdentifier() {
+          return deserializerIdentifier;
+        }
...
+  private static final int deserializerIdentifier = CacheableDeserializerIdManager
+      .registerDeserializer(blockDeserializer);
{code}
                
> Bucket Cache:A solution about CMS,Heap Fragment and Big Cache on HBASE
> ----------------------------------------------------------------------
>
>                 Key: HBASE-7404
>                 URL: https://issues.apache.org/jira/browse/HBASE-7404
>             Project: HBase
>          Issue Type: New Feature
>    Affects Versions: 0.94.3
>            Reporter: chunhui shen
>            Assignee: chunhui shen
>             Fix For: 0.96.0, 0.94.5
>
>         Attachments: BucketCache.pdf, hbase-7404-94v2.patch, hbase-7404-trunkv2.patch, hbase-7404-trunkv9.patch, Introduction of Bucket Cache.pdf
>
>
> First, thanks @neil from Fusion-IO share the source code.
> What's Bucket Cache? 
> It could greatly decrease CMS and heap fragment by GC
> It support a large cache space for High Read Performance by using high speed disk like Fusion-io
> 1.An implementation of block cache like LruBlockCache
> 2.Self manage blocks' storage position through Bucket Allocator
> 3.The cached blocks could be stored in the memory or file system
> 4.Bucket Cache could be used as a mainly block cache(see CombinedBlockCache), combined with LruBlockCache to decrease CMS and fragment by GC.
> 5.BucketCache also could be used as a secondary cache(e.g. using Fusionio to store block) to enlarge cache space
> How about SlabCache?
> We have studied and test SlabCache first, but the result is bad, because:
> 1.SlabCache use SingleSizeCache, its use ratio of memory is low because kinds of block size, especially using DataBlockEncoding
> 2.SlabCache is uesd in DoubleBlockCache, block is cached both in SlabCache and LruBlockCache, put the block to LruBlockCache again if hit in SlabCache , it causes CMS and heap fragment don't get any better
> 3.Direct heap performance is not good as heap, and maybe cause OOM, so we recommend using "heap" engine 
> See more in the attachment and in the patch

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