Mailing-List: contact hbase-dev-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: hbase-dev@hadoop.apache.org
Message-ID: <10520195.13831273728164242.JavaMail.jira@thor>
Date: Thu, 13 May 2010 01:22:44 -0400 (EDT)
From: "stack (JIRA)" <jira@apache.org>
To: hbase-dev@hadoop.apache.org
Subject: [jira] Resolved: (HBASE-1246) BloomFilter's use of BitSet is too
 inefficient
In-Reply-To: <108811871.1236333957584.JavaMail.jira@brutus>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


     [ https://issues.apache.org/jira/browse/HBASE-1246?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

stack resolved HBASE-1246.
--------------------------

    Resolution: Fixed

Resolving

> BloomFilter's use of BitSet is too inefficient
> ----------------------------------------------
>
>                 Key: HBASE-1246
>                 URL: https://issues.apache.org/jira/browse/HBASE-1246
>             Project: Hadoop HBase
>          Issue Type: Bug
>    Affects Versions: 0.20.0
>         Environment: Java 1.6, OSX 64 bit
>            Reporter: ryan rawson
>            Assignee: Nicolas Spiegelberg
>             Fix For: 0.22.0
>
>         Attachments: ByteBloomFilter.java
>
>
> From the logfile run of TestBloomFilter with special SizeOf agent jar:
> Writing bloom filter for: hdfs://localhost:64003/user/ryan/testComputedParameters/1278366260/contents/6159869037185296839 for size: 100
> 2009-03-06 01:54:25,491 DEBUG [RegionServer:0.cacheFlusher] regionserver.StoreFile$StoreFileWriter(319): New bloom filter: vectorSize: 1175 hash_count: 5 numKeys: 100
> Serialized bloomfilter size: 160
> In memory bf size: 1248
> As we can see, the bit vector is 1175 bits, and the serialized size is fairly compact - 160 bytes.
> But the in-memory size is nearly 10x bigger than it has to be.  Looking in BloomFilter we see:
>   BitSet bits;
> is the only field.
> Clearly it seems the BitSet is using 1 byte = 1 bit.  That is an 8 time expansion of where we should be.
> Considering every HFile could potentially have a bloom filter, and bloom filters are more likely to have bit vector sizes of 10,000-100,000, we should do something about this.  Aka: write our own bit-set that uses byte[] and bit ops.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.