VII. Internals

This part contains assorted information that might be of use to PostgreSQL developers.

Table of Contents

44. Overview of PostgreSQL Internals

44.1. The Path of a Query

44.2. How Connections are Established

44.3. The Parser Stage

44.4. The PostgreSQL Rule System

44.5. Planner/Optimizer

44.6. Executor

45. System Catalogs

45.1. Overview

45.2. pg_aggregate

45.3. pg_am

45.4. pg_amop

45.5. pg_amproc

45.6. pg_attrdef

45.7. pg_attribute

45.8. pg_authid

45.9. pg_auth_members

45.10. pg_cast

45.11. pg_class

45.12. pg_constraint

45.13. pg_conversion

45.14. pg_database

45.15. pg_db_role_setting

45.16. pg_default_acl

45.17. pg_depend

45.18. pg_description

45.19. pg_enum

45.20. pg_foreign_data_wrapper

45.21. pg_foreign_server

45.22. pg_index

45.23. pg_inherits

45.24. pg_language

45.25. pg_largeobject

45.26. pg_largeobject_metadata

45.27. pg_namespace

45.28. pg_opclass

45.29. pg_operator

45.30. pg_opfamily

45.31. pg_pltemplate

45.32. pg_proc

45.33. pg_rewrite

45.34. pg_shdepend

45.35. pg_shdescription

45.36. pg_statistic

45.37. pg_tablespace

45.38. pg_trigger

45.39. pg_ts_config

45.40. pg_ts_config_map

45.41. pg_ts_dict

45.42. pg_ts_parser

45.43. pg_ts_template

45.44. pg_type

45.45. pg_user_mapping

45.46. System Views

45.47. pg_cursors

45.48. pg_group

45.49. pg_indexes

45.50. pg_locks

45.51. pg_prepared_statements

45.52. pg_prepared_xacts

45.53. pg_roles

45.54. pg_rules

45.55. pg_settings

45.56. pg_shadow

45.57. pg_stats

45.58. pg_tables

45.59. pg_timezone_abbrevs

45.60. pg_timezone_names

45.61. pg_user

45.62. pg_user_mappings

45.63. pg_views

46. Frontend/Backend Protocol

46.1. Overview

46.2. Message Flow

46.3. Streaming Replication Protocol

46.4. Message Data Types

46.5. Message Formats

46.6. Error and Notice Message Fields

46.7. Summary of Changes since Protocol 2.0

47. PostgreSQL Coding Conventions

47.1. Formatting

47.2. Reporting Errors Within the Server

47.3. Error Message Style Guide

48. Native Language Support

48.1. For the Translator

48.2. For the Programmer

49. Writing A Procedural Language Handler

50. Genetic Query Optimizer

50.1. Query Handling as a Complex Optimization Problem

50.2. Genetic Algorithms

50.3. Genetic Query Optimization (GEQO) in PostgreSQL

50.4. Further Reading

51. Index Access Method Interface Definition

51.1. Catalog Entries for Indexes

51.2. Index Access Method Functions

51.3. Index Scanning

51.4. Index Locking Considerations

51.5. Index Uniqueness Checks

51.6. Index Cost Estimation Functions

52. GiST Indexes

52.1. Introduction

52.2. Extensibility

52.3. Implementation

52.4. Examples

52.5. Crash Recovery

53. GIN Indexes

53.1. Introduction

53.2. Extensibility

53.3. Implementation

53.4. GIN tips and tricks

53.5. Limitations

53.6. Examples

54. Database Physical Storage

54.1. Database File Layout

54.2. TOAST

54.3. Free Space Map

54.4. Visibility Map

54.5. Database Page Layout

55. BKI Backend Interface

55.1. BKI File Format

55.2. BKI Commands

55.3. Structure of the Bootstrap BKI File

55.4. Example

56. How the Planner Uses Statistics

56.1. Row Estimation Examples