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1. Query Engine 1.1. Relational Model 关系型数据库是建模现实世界的关联数据的有组织的集合。最早期数据库难于构建，逻辑与物理层强耦合。 查询流程 SQL（Parser）：词法分析和语法分析。 ...

1. Overview 最初的TCP因为不支持拥塞控制而频繁被丢弃数据包，协议栈被投入使用8年后，Van Jacobson在1988年将 TCP 拥塞控制引入网络。 IP层并没有提供拥塞控制功能，各个主机不知道什么是合理的速度。理想场景利用负反馈控制窗口，每一个TCP连接，引入变量CongestionWindow与SlowStartThreshold。 ...

The Eight Fallacies of Distributed Computing by Peter Deutsch. Essentially everyone, when they first build a distributed application, makes the following eight assumptions. All prove to be false in the long run and all cause big trouble and painful learning experiences. The network is reliable Latency is zero Bandwidth is infinite The network is secure Topology doesn’t change There is one administrator Transport cost is zero The network is homogeneous 1. 2PC XA规范中定义的分布式事务模型包括四个组成部分： ...

1. Definition of security confidentiality: only sender, intended receiver should “understand” message contents sender encrypts message receiver decrypts message authentication: sender, receiver want to confirm identity of each other message integrity: sender, receiver want to ensure message not altered (in transit, or afterwards) without detection access and availability: services must be accessible and available to users. Access is the basis of availability. Without network security, the intruder can eavesdrop, insert messages, impersonation, hijacking(taking over ongoing connection), denial of service and so on. ...

AKF Availability Cube 随着业务规模增长，拆解单体应用（monolith），设计成为面向服务架构（Service-oriented architectutre），做成一个个微服务（Micro-service）已经是如今的大趋势。 ...