9bNine Bits

How databases actually work

Plain explanations of PostgreSQL internals, graph data modeling and the big-data stack, each with a worked example and the trade-offs that matter in production.

PostgreSQL JSONB Internals and IndexingBitmap Index Scan in PostgreSQL: How It Works and When It AppearsAdvantages of PostgreSQLConstant Values in PostgreSQLPL/pgSQL Internals: How PostgreSQL Compiles and Executes ProceduresPostgreSQL Architecture: Processes, Memory, and WALPostgreSQL's Indexes: How They Work and When to Use ThemHow the PostgreSQL Query Optimizer WorksRelcache in PostgreSQL: How the Relation Cache WorksWhat Is PostGIS?What Is PostgreSQL?SQL: The Technology That Never Left Is BackSQL vs NoSQL: Comparative Advantages and DisadvantagesWhy Uber Moved From PostgreSQL to MySQLPostgreSQLRelational Databases vs. Graph DatabasesWhat Is a Graph Database?Building Graph-Powered Applications with Node.js and TypeScriptComparing Knowledge Graphs in RDF and Graph DatabasesCross-Domain Data in Graph DatabasesData Modeling: How Relational, Graph, and Big-Data Systems Structure InformationExplainable AI and Graph DatabasesHow Fraud Detection Systems Use Graph DatabasesGeo Data Processing Using Graph DatabasesGraph Analysis Algorithms: Centrality, Cliques, and ComponentsGraph Analysis Platforms: What They Are and How They WorkGraph Database Comparison: Storage, Clustering, and FailoverGraph Database Use Case: Recommendation EnginesGraph Database Recommendation Engine: How It WorksA History of Databases and Graph DatabasesHow to Implement Project Data in a Graph DatabaseHow Cypher Works With Ruby to Query a Graph Database InstanceMaster Data Management Using a Graph DatabaseGraphHow Apache Spark Works, and How It Fits with HDFS and HBaseHBase Functionality: Tables, Schema, and Cluster InternalsApache Hive: How It Works and When to Use ItHive and HiveQL: SQL on Hadoop ExplainedApache Spark Explained: How It Works With HDFS, Sqoop, and Graph DataWhat Is Apache Oozie? Workflow Scheduling for HadoopApache Oozie Workflow: How It Works and When to Use ItWhat Is Sqoop and How Does It Move Data Between Hadoop and Relational Databases?Understanding Apache Kafka: Architecture, Internals, and Trade-offsWhat Is HBase and How Does It Work?Understanding HDFS: Architecture, Data Flow, and Trade-offsWhat Is MapReduce and How Does It Work?Apache YARN: How Hadoop's Resource Manager WorksApache ZooKeeper Explained: Coordination for Distributed SystemsHive 2 and Hive 3 Features: What Changed and Why It MattersBig data

Each point is a page. Select one to open it.

PostgreSQL

Indexes, the query planner, JSONB and other internals of the database most teams already run.

Graph databases

Data modeling, query languages and the problems graphs solve better than tables.

Big data systems

HDFS, Kafka, Spark and the rest of the stack, and how the pieces fit.