Mitsunori Komatsu komamitsu

Download the source code

git clone https://github.com/yugabyte/yugabyte-db.git
cd yugabyte-db

Start minikube

$ minikube start --cpus=4

$ helm repo add k8ssandra https://helm.k8ssandra.io/stable

[Unit]
Description=xremap service
After=default.target

[Service]

	# Wormhole4j v0.3.0: Adding Multi-threaded Concurrency

	## 1. Introduction

	- Quick recap of Wormhole4j
	- What changed in v0.3.0 (real multi-thread support)
	- Why this matters

	---

	### Blog Post Structure: "Scaling Wormhole4j: Lock-Free Concurrency and Verified Correctness"

	#### 1. Introduction: The Evolution
	* The Mission: Briefly recap the original Wormhole paper (EuroSys '19) goal: a fast $O(\log L)$ ordered index.
	* The Problem: While the original was a performance breakthrough, it was strictly single-threaded. Real-world infrastructure requires concurrency.
	* The Announcement: Introduce v0.3.0, the culmination of adding multi-threaded support while preserving the core performance advantages.

	#### 2. The Architecture of Concurrency
	* The Structural Conflict: Explain why concurrent ordered indexes are difficult—modifications like splits/merges ripple through both the `LeafList` and the `MetaTrieHT`, creating a bottleneck.
	* The Three-Layer Strategy: Explain the concurrency model:

	# Wormhole4j 0.3: Thread-Safe Concurrent Access

	## 1. Introduction
	- Recap of Wormhole4j: fast ordered map, O(log L) lookups, EuroSys '19 paper
	- The gap: single-threaded only until now
	- What this post covers: design, correctness verification, benchmarks

	## 2. Why Concurrent Ordered Indexes Are Hard
	- Maintaining order + range scans rules out simple approaches
	- The specific problem: splits/merges modify both the LeafList

	import com.fasterxml.jackson.annotation.JsonCreator;
	import com.fasterxml.jackson.annotation.JsonProperty;
	import com.fasterxml.jackson.core.JsonProcessingException;
	import com.fasterxml.jackson.databind.ObjectMapper;
	import org.apache.fury.Fury;
	import org.apache.fury.config.Language;
	import org.msgpack.jackson.dataformat.MessagePackMapper;

	import java.io.IOException;
	import java.util.*;

	package org.example;

	import java.sql.Connection;
	import java.sql.PreparedStatement;
	import java.sql.ResultSet;
	import java.sql.SQLException;
	import java.sql.Statement;
	import java.util.Arrays;
	import java.util.HashMap;
	import java.util.Map;

	package org.komamitsu.unixdomainsockettest;

	import java.net.StandardProtocolFamily;
	import java.net.UnixDomainSocketAddress;
	import java.nio.ByteBuffer;
	import java.nio.channels.ServerSocketChannel;
	import java.nio.channels.SocketChannel;
	import java.nio.file.Path;
	import java.nio.file.Paths;
	import java.util.ArrayList;