7. Server Programming

This part is about extending the server functionality with user-defined functions, data types, triggers, etc. These are advanced topics which should probably 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 languages. It is essential to read at least the earlier sections of extend (covering functions) before diving into the material about server-side programming languages.

• 7.1. Extending SQL
  • 7.1.1. How Extensibility Works
  • 7.1.2. The PostgreSQL Type System
    • 7.1.2.1. Base Types
    • 7.1.2.2. Container Types
    • 7.1.2.3. Domains
    • 7.1.2.4. Pseudo-Types
    • 7.1.2.5. Polymorphic Types
  • 7.1.3. Packaging Related Objects into an Extension
    • 7.1.3.1. Extension Files
    • 7.1.3.2. Extension Relocatability
    • 7.1.3.3. Extension Configuration Tables
    • 7.1.3.4. Extension Updates
    • 7.1.3.5. Installing Extensions Using Update Scripts
    • 7.1.3.6. Security Considerations for Extensions
    • 7.1.3.7. Extension Example
  • 7.1.4. Extension Building Infrastructure
• 7.2. Triggers
  • 7.2.1. Overview of Trigger Behavior
  • 7.2.2. Visibility of Data Changes
  • 7.2.3. Writing Trigger Functions in C
  • 7.2.4. A Complete Trigger Example
• 7.3. Event Triggers
  • 7.3.1. Overview of Event Trigger Behavior
  • 7.3.2. Event Trigger Firing Matrix
  • 7.3.3. Writing Event Trigger Functions in C
  • 7.3.4. A Complete Event Trigger Example
  • 7.3.5. A Table Rewrite Event Trigger Example
• 7.4. The Rule System
  • 7.4.1. The Query Tree
  • 7.4.2. Views and the Rule System
    • 7.4.2.1. How SELECT Rules Work
    • 7.4.2.2. View Rules in Non-SELECT Statements
    • 7.4.2.3. The Power of Views in PostgreSQL
    • 7.4.2.4. Updating a View
  • 7.4.3. Materialized Views
  • 7.4.4. Rules on INSERT, UPDATE, and DELETE
    • 7.4.4.1. How Update Rules Work
    • 7.4.4.2. Cooperation with Views
  • 7.4.5. Rules and Privileges
  • 7.4.6. Rules and Command Status
  • 7.4.7. Rules Versus Triggers
• 7.5. Procedural Languages
  • 7.5.1. Installing Procedural Languages
    • 7.5.1.1. Manual Installation of PL/Perl
• 7.6. PL/Tcl — Tcl Procedural Language
  • 7.6.1. Overview
  • 7.6.2. PL/Tcl Functions and Arguments
  • 7.6.3. Data Values in PL/Tcl
  • 7.6.4. Global Data in PL/Tcl
  • 7.6.5. Database Access from PL/Tcl
  • 7.6.6. Trigger Functions in PL/Tcl
  • 7.6.7. Event Trigger Functions in PL/Tcl
  • 7.6.8. Error Handling in PL/Tcl
  • 7.6.9. Explicit Subtransactions in PL/Tcl
  • 7.6.10. Transaction Management
  • 7.6.11. PL/Tcl Configuration
  • 7.6.12. Tcl Procedure Names
• 7.7. PL/Perl — Perl Procedural Language
  • 7.7.1. PL/Perl Functions and Arguments
  • 7.7.2. Data Values in PL/Perl
  • 7.7.3. Built-in Functions
    • 7.7.3.1. Database Access from PL/Perl
    • 7.7.3.2. Utility Functions in PL/Perl
  • 7.7.4. Global Values in PL/Perl
  • 7.7.5. Trusted and Untrusted PL/Perl
  • 7.7.6. PL/Perl Triggers
  • 7.7.7. PL/Perl Event Triggers
  • 7.7.8. PL/Perl Under the Hood
    • 7.7.8.1. Configuration
    • 7.7.8.2. Limitations and Missing Features
• 7.8. PL/Python — Python Procedural Language
  • 7.8.1. PL/Python Functions
  • 7.8.2. Data Values
    • 7.8.2.1. Data Type Mapping
    • 7.8.2.2. Null, None
    • 7.8.2.3. Arrays, Lists
    • 7.8.2.4. Composite Types
    • 7.8.2.5. Set-Returning Functions
  • 7.8.3. Sharing Data
  • 7.8.4. Anonymous Code Blocks
  • 7.8.5. Trigger Functions
  • 7.8.6. Database Access
    • 7.8.6.1. Database Access Functions
    • 7.8.6.2. Trapping Errors
  • 7.8.7. Explicit Subtransactions
    • 7.8.7.1. Subtransaction Context Managers
  • 7.8.8. Transaction Management
  • 7.8.9. Utility Functions
  • 7.8.10. Python 2 vs. Python 3
  • 7.8.11. Environment Variables
• 7.9. Server Programming Interface
  • 7.9.1. Interface Functions
  • 7.9.2. Description
  • 7.9.3. Return Value
  • 7.9.4. Description
  • 7.9.5. Return Value
  • 7.9.6. Description
  • 7.9.7. Arguments
  • 7.9.8. Return Value
  • 7.9.9. Notes
  • 7.9.10. Description
  • 7.9.11. Arguments
  • 7.9.12. Return Value
  • 7.9.13. Description
  • 7.9.14. Arguments
  • 7.9.15. Return Value
  • 7.9.16. Description
  • 7.9.17. Arguments
  • 7.9.18. Return Value
  • 7.9.19. Description
  • 7.9.20. Arguments
  • 7.9.21. Return Value
  • 7.9.22. Notes
  • 7.9.23. Description
  • 7.9.24. Arguments
  • 7.9.25. Return Value
  • 7.9.26. Notes
  • 7.9.27. Description
  • 7.9.28. Arguments
  • 7.9.29. Return Value
  • 7.9.30. Description
  • 7.9.31. Arguments
  • 7.9.32. Return Value
  • 7.9.33. Description
  • 7.9.34. Arguments
  • 7.9.35. Return Value
  • 7.9.36. Description
  • 7.9.37. Arguments
  • 7.9.38. Return Value
  • 7.9.39. Description
  • 7.9.40. Arguments
  • 7.9.41. Return Value
  • 7.9.42. Description
  • 7.9.43. Arguments
  • 7.9.44. Return Value
  • 7.9.45. Description
  • 7.9.46. Arguments
  • 7.9.47. Return Value
  • 7.9.48. Description
  • 7.9.49. Arguments
  • 7.9.50. Return Value
  • 7.9.51. Description
  • 7.9.52. Arguments
  • 7.9.53. Return Value
  • 7.9.54. Description
  • 7.9.55. Arguments
  • 7.9.56. Return Value
  • 7.9.57. Description
  • 7.9.58. Arguments
  • 7.9.59. Return Value
  • 7.9.60. Description
  • 7.9.61. Arguments
  • 7.9.62. Return Value
  • 7.9.63. Description
  • 7.9.64. Arguments
  • 7.9.65. Return Value
  • 7.9.66. Description
  • 7.9.67. Arguments
  • 7.9.68. Return Value
  • 7.9.69. Description
  • 7.9.70. Arguments
  • 7.9.71. Return Value
  • 7.9.72. Notes
  • 7.9.73. Description
  • 7.9.74. Arguments
  • 7.9.75. Notes
  • 7.9.76. Description
  • 7.9.77. Arguments
  • 7.9.78. Return Value
  • 7.9.79. Notes
  • 7.9.80. Description
  • 7.9.81. Arguments
  • 7.9.82. Return Value
  • 7.9.83. Notes
  • 7.9.84. Description
  • 7.9.85. Arguments
  • 7.9.86. Description
  • 7.9.87. Arguments
  • 7.9.88. Return Value
  • 7.9.89. Notes
  • 7.9.90. Description
  • 7.9.91. Arguments
  • 7.9.92. Return Value
  • 7.9.93. Notes
  • 7.9.94. Description
  • 7.9.95. Arguments
  • 7.9.96. Return Value
  • 7.9.97. Description
  • 7.9.98. Arguments
  • 7.9.99. Return Value
  • 7.9.100. Description
  • 7.9.101. Arguments
  • 7.9.102. Return Value
  • 7.9.103. Interface Support Functions
  • 7.9.104. Description
  • 7.9.105. Arguments
  • 7.9.106. Return Value
  • 7.9.107. Description
  • 7.9.108. Arguments
  • 7.9.109. Return Value
  • 7.9.110. Description
  • 7.9.111. Arguments
  • 7.9.112. Return Value
  • 7.9.113. Description
  • 7.9.114. Arguments
  • 7.9.115. Return Value
  • 7.9.116. Description
  • 7.9.117. Arguments
  • 7.9.118. Return Value
  • 7.9.119. Description
  • 7.9.120. Arguments
  • 7.9.121. Return Value
  • 7.9.122. Description
  • 7.9.123. Arguments
  • 7.9.124. Return Value
  • 7.9.125. Description
  • 7.9.126. Arguments
  • 7.9.127. Return Value
  • 7.9.128. Description
  • 7.9.129. Arguments
  • 7.9.130. Return Value
  • 7.9.131. Memory Management
  • 7.9.132. Description
  • 7.9.133. Arguments
  • 7.9.134. Return Value
  • 7.9.135. Description
  • 7.9.136. Arguments
  • 7.9.137. Return Value
  • 7.9.138. Description
  • 7.9.139. Arguments
  • 7.9.140. Description
  • 7.9.141. Arguments
  • 7.9.142. Return Value
  • 7.9.143. Description
  • 7.9.144. Arguments
  • 7.9.145. Return Value
  • 7.9.146. Description
  • 7.9.147. Arguments
  • 7.9.148. Return Value
  • 7.9.149. Description
  • 7.9.150. Arguments
  • 7.9.151. Description
  • 7.9.152. Arguments
  • 7.9.153. Description
  • 7.9.154. Arguments
  • 7.9.155. Return Value
  • 7.9.156. Transaction Management
  • 7.9.157. Description
  • 7.9.158. Description
  • 7.9.159. Description
  • 7.9.160. Visibility of Data Changes
  • 7.9.161. Examples
• 7.10. Background Worker Processes
• 7.11. Logical Decoding
  • 7.11.1. Logical Decoding Examples
  • 7.11.2. Logical Decoding Concepts
    • 7.11.2.1. Logical Decoding
    • 7.11.2.2. Replication Slots
    • 7.11.2.3. Output Plugins
    • 7.11.2.4. Exported Snapshots
  • 7.11.3. Streaming Replication Protocol Interface
  • 7.11.4. Logical Decoding SQL Interface
  • 7.11.5. System Catalogs Related to Logical Decoding
  • 7.11.6. Logical Decoding Output Plugins
    • 7.11.6.1. Initialization Function
    • 7.11.6.2. Capabilities
    • 7.11.6.3. Output Modes
    • 7.11.6.4. Output Plugin Callbacks
    • 7.11.6.5. Functions for Producing Output
  • 7.11.7. Logical Decoding Output Writers
  • 7.11.8. Synchronous Replication Support for Logical Decoding
    • 7.11.8.1. Overview
    • 7.11.8.2. Caveats
  • 7.11.9. Streaming of Large Transactions for Logical Decoding
  • 7.11.10. Two-phase Commit Support for Logical Decoding
• 7.12. Replication Progress Tracking
• 7.13. Archive Modules
  • 7.13.1. Initialization Functions
  • 7.13.2. Archive Module Callbacks
    • 7.13.2.1. Check Callback
    • 7.13.2.2. Archive Callback
    • 7.13.2.3. Shutdown Callback