cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Branimir Lambov (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-7039) DirectByteBuffer compatible LZ4 methods
Date Fri, 28 Nov 2014 13:54:13 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-7039?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Branimir Lambov updated CASSANDRA-7039:
---------------------------------------
    Attachment: 7039.patch

Attached patch updates the lz4-java library to 1.3.0.

> DirectByteBuffer compatible LZ4 methods
> ---------------------------------------
>
>                 Key: CASSANDRA-7039
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7039
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Benedict
>            Assignee: Branimir Lambov
>            Priority: Minor
>              Labels: performance
>             Fix For: 3.0
>
>         Attachments: 7039.patch
>
>
> As we move more things off-heap, it's becoming more and more essential to be able to
use DirectByteBuffer (or native pointers) in various places. Unfortunately LZ4 doesn't currently
support this operation, despite being JNI based - this means we both have to perform unnecessary
copies to de/compress data from DBB, but also we can stall GC as any JNI method operating
over a java array using the GetPrimitiveArrayCritical enters a critical section that prevents
GC for its duration. This means STWs will be at least as long any running compression/decompression
(and no GC will happen until they complete, so it's additive).
> We should temporarily fork (and then resubmit upstream) jpountz-lz4 to support operating
over a native pointer, so that we can pass a DBB or a raw pointer we have allocated ourselves.
This will help improve performance when flushing the new offheap memtables, as well as enable
us to implement CASSANDRA-6726 and finish CASSANDRA-4338.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message