Part V. Server Programming

   This part is about extending the server functionality with user-defined
   functions, data types, triggers, etc. These are advanced topics which
   should be approached only after all the other user documentation about
   PostgreSQL has been understood. Later chapters in this part describe
   the server-side programming languages available in the PostgreSQL
   distribution as well as general issues concerning server-side
   programming. It is essential to read at least the earlier sections of
   Chapter 36 (covering functions) before diving into the material about
   server-side programming.

   Table of Contents

   36. Extending SQL

        36.1. How Extensibility Works
        36.2. The PostgreSQL Type System
        36.3. User-Defined Functions
        36.4. User-Defined Procedures
        36.5. Query Language (SQL) Functions
        36.6. Function Overloading
        36.7. Function Volatility Categories
        36.8. Procedural Language Functions
        36.9. Internal Functions
        36.10. C-Language Functions
        36.11. Function Optimization Information
        36.12. User-Defined Aggregates
        36.13. User-Defined Types
        36.14. User-Defined Operators
        36.15. Operator Optimization Information
        36.16. Interfacing Extensions to Indexes
        36.17. Packaging Related Objects into an Extension
        36.18. Extension Building Infrastructure

   37. Triggers

        37.1. Overview of Trigger Behavior
        37.2. Visibility of Data Changes
        37.3. Writing Trigger Functions in C
        37.4. A Complete Trigger Example

   38. Event Triggers

        38.1. Overview of Event Trigger Behavior
        38.2. Writing Event Trigger Functions in C
        38.3. A Complete Event Trigger Example
        38.4. A Table Rewrite Event Trigger Example
        38.5. A Database Login Event Trigger Example

   39. The Rule System

        39.1. The Query Tree
        39.2. Views and the Rule System
        39.3. Materialized Views
        39.4. Rules on INSERT, UPDATE, and DELETE
        39.5. Rules and Privileges
        39.6. Rules and Command Status
        39.7. Rules Versus Triggers

   40. Procedural Languages

        40.1. Installing Procedural Languages

   41. PL/pgSQL — SQL Procedural Language

        41.1. Overview
        41.2. Structure of PL/pgSQL
        41.3. Declarations
        41.4. Expressions
        41.5. Basic Statements
        41.6. Control Structures
        41.7. Cursors
        41.8. Transaction Management
        41.9. Errors and Messages
        41.10. Trigger Functions
        41.11. PL/pgSQL under the Hood
        41.12. Tips for Developing in PL/pgSQL
        41.13. Porting from Oracle PL/SQL

   42. PL/Tcl — Tcl Procedural Language

        42.1. Overview
        42.2. PL/Tcl Functions and Arguments
        42.3. Data Values in PL/Tcl
        42.4. Global Data in PL/Tcl
        42.5. Database Access from PL/Tcl
        42.6. Trigger Functions in PL/Tcl
        42.7. Event Trigger Functions in PL/Tcl
        42.8. Error Handling in PL/Tcl
        42.9. Explicit Subtransactions in PL/Tcl
        42.10. Transaction Management
        42.11. PL/Tcl Configuration
        42.12. Tcl Procedure Names

   43. PL/Perl — Perl Procedural Language

        43.1. PL/Perl Functions and Arguments
        43.2. Data Values in PL/Perl
        43.3. Built-in Functions
        43.4. Global Values in PL/Perl
        43.5. Trusted and Untrusted PL/Perl
        43.6. PL/Perl Triggers
        43.7. PL/Perl Event Triggers
        43.8. PL/Perl Under the Hood

   44. PL/Python — Python Procedural Language

        44.1. PL/Python Functions
        44.2. Data Values
        44.3. Sharing Data
        44.4. Anonymous Code Blocks
        44.5. Trigger Functions
        44.6. Database Access
        44.7. Explicit Subtransactions
        44.8. Transaction Management
        44.9. Utility Functions
        44.10. Python 2 vs. Python 3
        44.11. Environment Variables

   45. Server Programming Interface

        45.1. Interface Functions
        45.2. Interface Support Functions
        45.3. Memory Management
        45.4. Transaction Management
        45.5. Visibility of Data Changes
        45.6. Examples

   46. Background Worker Processes
   47. Logical Decoding

        47.1. Logical Decoding Examples
        47.2. Logical Decoding Concepts
        47.3. Streaming Replication Protocol Interface
        47.4. Logical Decoding SQL Interface
        47.5. System Catalogs Related to Logical Decoding
        47.6. Logical Decoding Output Plugins
        47.7. Logical Decoding Output Writers
        47.8. Synchronous Replication Support for Logical Decoding
        47.9. Streaming of Large Transactions for Logical Decoding
        47.10. Two-phase Commit Support for Logical Decoding

   48. Replication Progress Tracking
   49. Archive Modules

        49.1. Initialization Functions
        49.2. Archive Module Callbacks

   50. OAuth Validator Modules

        50.1. Safely Designing a Validator Module
        50.2. Initialization Functions
        50.3. OAuth Validator Callbacks