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  MySQL Index Merge Optimization Practices

In production environment databases, it is often seen that some SQL where conditions include: equal condition on a normal index + primary key range query + order by limit Although using a normal index would be more efficient, the system chooses to use index merge instead in some cases. This article explores such index merge situations. Index Merge Official Introduction   The Index Merge access method retrieves rows with multiple range scans and merges their results into one. Generall...

   INDEX MERGE,MYSQL,PRIMARY INDEX,SECONDARY INDEX     2024-09-10 04:52:26

  IoT System Cyber Attack Case Study 02: Python Deserialization Attack and Library Hijacking Attack

Project Design Purpose: The objective of this cyber attack case study is to develop a workshop that demonstrates how a red team attacker can permanently compromise a people detection radar IoT device. The attack path is achieved through a series of attacks, including traffic eavesdropping, data deserialization attacks, web shell attacks, remote command/code execution, and Python library hijacking attacks. This case study is intended for IoT and data security professional training, aiming to ill...

       2024-07-14 01:40:09

  Python PLC Honeypot Project

Program Design Propose : This project aims to develop a sophisticated honeypot system that emulates an OT (Operational Technology) SCADA network environment, bridging Level 1 OT field controller devices (PLCs) with Level 2 control programs, including Human-Machine Interfaces (HMIs). This honeypot will simulate various PLC models from major vendors, such as Schneider and Siemens, while supporting the primary communication protocols Modbus-TCP and Siemens-S7Comm. The system will integrate essenti...

       2024-11-25 03:56:49

  2D Indoor CQB Robot Simulation

Program Design Purpose: The integration of robots in Close Quarters Battle (CQB) represents a significant advancement in modern military and law enforcement tactics. These robots, designed to navigate tight spaces, gather real-time intelligence, and engage threats, are invaluable assets in high-stakes scenarios. Our goal is to develop a 2D tactical board simulation system, similar to a computer game, that can load building floor blueprints, display CQB squad (robot) positions, enemy locations, ...

       2024-08-11 08:40:31

  SIEM Big Data Visualization [03]:Graph-Based SIEM Log Analysis Dashboard

Program Design Purpose: The purpose of this program is to develop a Graph-Based SIEM (System Information and Event Management) dashboard that visualizes network communication patterns by processing and analyzing logs from IDS, firewalls, host computers, and other security devices. This dashboard will help security analysts quickly identify and investigate potential threats by using a Cytoscape-style Node-Edge graph for intuitive data representation. The program is an angular plug in which can i...

       2024-10-26 04:31:11

  Why (offset, limit) is slow in database select?

Starting from a problem Five years ago when I was working at Tencent, I found that MySQL request speed was very slow in the pagination scenario. With only 100,000 data, a select query on a single machine took about 2-3 seconds. I asked my mentor why, and he asked in return, "In an indexing scenario, what is the time complexity to get the nth largest number in MySQL?" The pursuit of the answer Confirming the scenario Assuming there is an index on the "status" column, a query like "select * from t...

   SLOW,LIMIT,OFFSET,MYSQL     2023-03-12 05:21:02

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