[CASSANDRA-3623] use MMapedBuffer in CompressedSegmentedFile.getSegment

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Fix Version/s: 1.1.0
• Component/s: Core
• Labels: compression
• Assignee: Vijay
• Reporter: Vijay
• Reviewer: Yuki Morishita
• Created: 13/Dec/11 17:36
• Updated: 08/Feb/12 19:25
• Resolved: 08/Feb/12 19:25

Description

CompressedSegmentedFile.getSegment seem to open a new file and doesnt seem to use the MMap and hence a higher CPU on the nodes and higher latencies on reads.

This ticket is to implement the TODO mentioned in CompressedRandomAccessReader

// TODO refactor this to separate concept of "buffer to avoid lots of read() syscalls" and "compression buffer"
but i think a separate class for the Buffer will be better.