Explore the intricacies of Terracotta's open-sourced OffHeap library in this 50-minute Devoxx conference talk. Delve into how this unique offheap library operates without byte code engineering, modified JVMs, non-standard APIs, or JNI. Discover its capabilities in providing maps and caches with minimal per-key heap overheads, scaling up to 6TB in a single node and 1TB in a single map. Learn how well-established computer science concepts from managed and unmanaged programming environments combine to create a stable, reliable, and useful library. Gain insights into map and cache best practices, JDK HashMap, OffHeap Map implementation, key and value storage techniques, native heap allocation, marshaling, and improved serialization methods. Explore concurrent map implementations, happens-before relationships, and solutions for enhanced write concurrency. Uncover the underlying principles that make this open-source project a powerful tool for efficient memory management and scalability in Java applications.
Overview
Syllabus
Intro
Who Am I?
A Bit of History
Problem Statement
Map/Cache Best Practices
Replace What?
JDK HashMap
OffHeap Map
Storing Key & Values
Options with 64 bits available
A Native Heap Allocator
Marshaling
Java Serialization Sucks
OffHeap's Serialization Sucks Less?
Where did the 59 bytes go?
Serialization is pretty malleable
j.u.c.ConcurrentMap
Happens Before Relationships
Simple solution
Moar Write Concurrency!
Conclusions
Additional Topics
Taught by
Devoxx
