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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-4153) Change getCodec method in BCFile's Compression class
Date Wed, 24 Feb 2016 23:21:18 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-4153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15166316#comment-15166316
] 

ASF GitHub Bot commented on ACCUMULO-4153:
------------------------------------------

Github user keith-turner commented on a diff in the pull request:

    https://github.com/apache/accumulo/pull/73#discussion_r54025034
  
    --- Diff: core/src/main/java/org/apache/accumulo/core/file/rfile/bcfile/Compression.java
---
    @@ -147,25 +148,27 @@ public synchronized OutputStream createCompressionStream(OutputStream
downStream
         },
     
         GZ(COMPRESSION_GZ) {
    -      private transient DefaultCodec codec;
    +      private transient AtomicReference<DefaultCodec> codec = new AtomicReference<DefaultCodec>();
     
           @Override
    -      synchronized CompressionCodec getCodec() {
    -        if (codec == null) {
    -          codec = new DefaultCodec();
    -          codec.setConf(conf);
    +      CompressionCodec getCodec() {
    +        DefaultCodec resultCodec = codec.get();
    +        if (null == resultCodec) {
    +          DefaultCodec newCodec = new DefaultCodec();
    +          newCodec.setConf(conf);
    +          codec.compareAndSet(null, newCodec);
             }
     
    -        return codec;
    +        return codec.get();
    --- End diff --
    
    > Seems like return resultCodec at the end would be more straightforward, no?
    
    Would be nice to avoid two reads of codec.


> Change getCodec method in BCFile's Compression class
> ----------------------------------------------------
>
>                 Key: ACCUMULO-4153
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-4153
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.6.5
>            Reporter: marco polo
>            Assignee: marco polo
>            Priority: Minor
>             Fix For: 1.6.6, 1.7.2, 1.8.0
>
>         Attachments: patchCompression
>
>
> Seeing major blockages blockages on the Synchronized method of getCodec.  My initial
change was to change it to double checked locking; however, spoke with [~kturner] and I'm
changing this to an AtomicReference. Have a patch for the former but am in the process of
testing the AtomicReference patch
> Note this is for Gzip



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