The SQL Query Roadtrip

The SQL Query Roadtrip

7 articles in this series •

Posts

  1. 1

    Overview

    • 11 min read

    Ever wonder what happens when you type SELECT * FROM users WHERE id = 42; and hit Enter? That simple query triggers a fascinating journey through PostgreSQL’s internals—a complex series of …

  2. 2

    Connections and Communication

    • 9 min read

    In the previous article , we explored the complete journey a SQL query takes through PostgreSQL—from parsing to execution. But before any of that can happen, your application needs to establish a …

  3. 3

    Parsing and Analysis

    • 12 min read

    In the previous article , we explored how PostgreSQL establishes connections and communicates using its wire protocol. Once your connection is established and the backend process is ready, you can …

  4. 4

    Query Rewriting

    • 11 min read

    In the previous article , we explored how PostgreSQL transforms SQL text into a validated Query tree through parsing and semantic analysis. By the end of that journey, PostgreSQL knows that your …

  5. 5

    The Query Planner

    • 19 min read

    In the previous article , we explored how PostgreSQL’s rewriter transforms queries—expanding views, applying security policies, and executing custom rules. By the end of that phase, your query …

  6. 6

    The Execution Engine

    • 15 min read

    In the previous article , we explored how PostgreSQL’s planner chooses the optimal execution strategy. The planner produces an abstract plan tree—nodes like “Sequential Scan,” …

  7. 7

    The Indexes

    • 31 min read

    When you create an index in PostgreSQL, you might think there’s just one type of index structure working behind the scenes. But PostgreSQL actually provides six different index types, each …