[jira] [Commented] (THRIFT-1469) Java isset space optimization

["Hudson (Commented) (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/THRIFT-1469?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13174368#comment-13174368 ] 

Hudson commented on THRIFT-1469:
--------------------------------

Integrated in Thrift #370 (See [https://builds.apache.org/job/Thrift/370/])
    THRIFT-1469. java: Java isset space optimization

This patch gives the generated code some variable-sized options for the isset bit vector. The compiler will attempt to use byte, short, int and long types before reverting to a BitSet for structs with a LOT of optional fields. This should save a fair amount of memory in a lot of cases.

Patch: Brian Bloniarz

bryanduxbury : http://svn.apache.org/viewvc/?view=rev&rev=1221828
Files : 
* /thrift/trunk/compiler/cpp/src/generate/t_java_generator.cc
* /thrift/trunk/lib/java/build.xml
* /thrift/trunk/lib/java/src/org/apache/thrift/EncodingUtils.java
* /thrift/trunk/lib/java/test/org/apache/thrift/TestOptionals.java
* /thrift/trunk/test/ManyOptionals.thrift

                
> Java isset space optimization
> -----------------------------
>
>                 Key: THRIFT-1469
>                 URL: https://issues.apache.org/jira/browse/THRIFT-1469
>             Project: Thrift
>          Issue Type: Improvement
>          Components: Java - Compiler
>    Affects Versions: 0.8
>            Reporter: Brian Bloniarz
>            Assignee: Brian Bloniarz
>            Priority: Minor
>              Labels: patch
>             Fix For: 0.9
>
>         Attachments: thrift-java-isset.patch
>
>
> Attached is a small patch and unit tests for Java to optimize the heapspace
> footprint of (for example):
> struct OptIntPair {
>     1: i32 a
>     2: i32 b
> }
> Each instance will have an __isset_bit_vector which points to a BitSet,
> which points to a long[], adding around 50 bytes of overhead to this object.
> The patch changes this by storing a raw byte and doing direct bitfield operations, like:
>   byte __isset_bitfield;
>   public void unsetB() {
>     __isset_bitfield = EncodingUtils.clearBit(__isset_bitfield, __B_ISSET_ID);
>   }
> A little nasty, but a big space win: on my machine, this brings down the total
> size of an OptIntPair from 85 bytes to 25 bytes. A BitSet gets used as a fallback
> when more than 64 __isset entries are needed.

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