The “Majority” in The Three-Body Problem
In The Three-Body Problem, Liu Cixin uses an immense historical canvas to explore the relationship between individuals and the collective. His doubts about Western democracy and the majority’s ability to determine its own fate run through the trilogy. Heroes struggle and sacrifice, only to see their work swept aside by history. Beginning with the Cultural Revolution, the story sets up a conflict between exceptional individuals and the ordinary masses, raising uncomfortable questions about humanity and society.
Daily 1.73K words
6.5840 Lab 1: MapReduce
Lab 1 asks us to implement a MapReduce system with two core components: a master and workers. This requires a good command of Go RPC and concurrent programming, along with a thorough understanding of the MapReduce workflow. I built two versions, starting with mutex locks and then moving to a more elegant channel-based implementation without explicit locks, whose design is simpler and clearer. The key to understanding the lab is to read the relevant documentation carefully, especially the flowcharts and explanations.
Notes 1.44K words
Reading the MapReduce Paper
MapReduce is an efficient parallel computing model designed to simplify processing large datasets. By defining the two key functions, Map and Reduce, users can break complex tasks into simple operations. The framework automatically handles data distribution and task scheduling, allowing developers to focus on the algorithm rather than low-level details. Its widespread use in distributed systems demonstrates its flexibility and practical value.
Notes 824 words
Setting Up the CSAPP Lab Environment
The labs are an essential part of learning CSAPP, but setting up Linux can be discouraging. Virtual machines bring installation errors, compatibility problems, and broken networking. WSL (Windows Subsystem for Linux), especially on Windows 10 version 2004 and later, provides a simpler, more direct Linux environment without the complexity and performance bottlenecks of a traditional VM.
Tinkering 1.06K words
MYDB 10. Implementing the Server, Client, and Wire Protocol
MYDB uses a client/server architecture similar to MySQL, allowing multiple clients to connect to a server over sockets, execute SQL queries, and receive results. Communication uses a special binary format, though plain text would also be an option for a simpler implementation. The basic transport structure supports effective communication and processing between client and server.
Projects 861 words
MYDB 9. Field and Table Management
The Table Manager (TBM) manages field and table structures. Parser turns SQL-like statements into structured representations, wrapping their information in the corresponding classes to simplify subsequent operations. This chapter also covers MYDB’s SQL syntax as a foundation for understanding the management process.
Projects 1.01K words
MYDB 8. Index Management
MYDB implements a clustered index using a B+ tree. IM interacts directly with the Data Manager (DM), bypassing the Version Manager (VM), so index data is written directly to the database file. This chapter details the binary-tree index structure and its basic node fields, including the leaf flag, key count, and sibling identifier, establishing the framework for indexed lookups.
Projects 830 words
MYDB 7. Deadlock Detection and the Version Manager
VM must handle version skipping introduced by MVCC as well as deadlocks. By simply marking a transaction, MYDB can cancel or roll it back and keep data from aborted transactions from affecting others. This design makes concurrent transaction handling more efficient and reliable, avoids the deadlock risks common with traditional 2PL, and improves overall stability and performance.
Projects 1.45K words
MYDB 6. Record Versions and Transaction Isolation
VM uses two-phase locking to ensure serializable schedules and introduces multiversion concurrency control (MVCC) to eliminate blocking between reads and writes. This chapter also defines conflicts between database operations, focusing on the interaction between updates and reads as a foundation for understanding transaction isolation levels.
Projects 1.73K words
MYDB 5. The Page Index and the Data Manager
The page index is an important part of DM, optimizing insertions by caching the free space available on each page. It lets higher-level modules quickly locate a suitable page without a lengthy search, making data operations more efficient. Its implementation works closely with the DataItem abstraction to support efficient database operation.
Projects 1.27K words
