System Design

What Is OLAP? OLTP vs OLAP Explained — The Complete Guide to Database Architecture

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What Is OLAP? OLTP vs OLAP Explained — The Complete Guide to Database Architecture

Every app you use runs on two very different kinds of database work. When you tap “buy” on an order, a database has to record that one purchase, instantly, correctly, without losing it. When a company later asks “how many orders did we get last month, broken down by city,” a database has to scan … Read more

What Is epoll? The Linux I/O Event Notification Mechanism Explained

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What Is epoll? Linux I/O Event Notification Explained

Every high-performance server you’ve ever used — Redis, Nginx, Node.js, HAProxy — has to answer the same basic question millions of times a second: which of the thousands of open network connections it’s holding actually has new data waiting to be read? Loop through every connection and ask “anything new?” and you’ll burn CPU cycles … Read more