Benedict updated CASSANDRA-7039:

    Assignee: Branimir Lambov  (was: Lyuben Todorov)

> 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
> 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

Reply via email to