Part VII. Internals

Table of Contents

50. Overview of PostgreSQL Internals

50.1. The Path of a Query

50.2. How Connections Are Established

50.3. The Parser Stage

50.4. The PostgreSQL Rule System

50.5. Planner/Optimizer

50.6. Executor

51. System Catalogs

51.1. Overview

51.2. pg_aggregate

51.3. pg_am

51.4. pg_amop

51.5. pg_amproc

51.6. pg_attrdef

51.7. pg_attribute

51.8. pg_authid

51.9. pg_auth_members

51.10. pg_cast

51.11. pg_class

51.12. pg_collation

51.13. pg_constraint

51.14. pg_conversion

51.15. pg_database

51.16. pg_db_role_setting

51.17. pg_default_acl

51.18. pg_depend

51.19. pg_description

51.20. pg_enum

51.21. pg_event_trigger

51.22. pg_extension

51.23. pg_foreign_data_wrapper

51.24. pg_foreign_server

51.25. pg_foreign_table

51.26. pg_index

51.27. pg_inherits

51.28. pg_init_privs

51.29. pg_language

51.30. pg_largeobject

51.31. pg_largeobject_metadata

51.32. pg_namespace

51.33. pg_opclass

51.34. pg_operator

51.35. pg_opfamily

51.36. pg_partitioned_table

51.37. pg_pltemplate

51.38. pg_policy

51.39. pg_proc

51.40. pg_publication

51.41. pg_publication_rel

51.42. pg_range

51.43. pg_replication_origin

51.44. pg_rewrite

51.45. pg_seclabel

51.46. pg_sequence

51.47. pg_shdepend

51.48. pg_shdescription

51.49. pg_shseclabel

51.50. pg_statistic

51.51. pg_statistic_ext

51.52. pg_statistic_ext_data

51.53. pg_subscription

51.54. pg_subscription_rel

51.55. pg_tablespace

51.56. pg_transform

51.57. pg_trigger

51.58. pg_ts_config

51.59. pg_ts_config_map

51.60. pg_ts_dict

51.61. pg_ts_parser

51.62. pg_ts_template

51.63. pg_type

51.64. pg_user_mapping

51.65. System Views

51.66. pg_available_extensions

51.67. pg_available_extension_versions

51.68. pg_config

51.69. pg_cursors

51.70. pg_file_settings

51.71. pg_group

51.72. pg_hba_file_rules

51.73. pg_indexes

51.74. pg_locks

51.75. pg_matviews

51.76. pg_policies

51.77. pg_prepared_statements

51.78. pg_prepared_xacts

51.79. pg_publication_tables

51.80. pg_replication_origin_status

51.81. pg_replication_slots

51.82. pg_roles

51.83. pg_rules

51.84. pg_seclabels

51.85. pg_sequences

51.86. pg_settings

51.87. pg_shadow

51.88. pg_stats

51.89. pg_stats_ext

51.90. pg_tables

51.91. pg_timezone_abbrevs

51.92. pg_timezone_names

51.93. pg_user

51.94. pg_user_mappings

51.95. pg_views

52. Frontend/Backend Protocol

52.1. Overview

52.2. Message Flow

52.3. SASL Authentication

52.4. Streaming Replication Protocol

52.5. Logical Streaming Replication Protocol

52.6. Message Data Types

52.7. Message Formats

52.8. Error and Notice Message Fields

52.9. Logical Replication Message Formats

52.10. Summary of Changes since Protocol 2.0

53. PostgreSQL Coding Conventions

53.1. Formatting

53.2. Reporting Errors Within the Server

53.3. Error Message Style Guide

53.4. Miscellaneous Coding Conventions

54. Native Language Support

54.1. For the Translator

54.2. For the Programmer

55. Writing a Procedural Language Handler

56. Writing a Foreign Data Wrapper

56.1. Foreign Data Wrapper Functions

56.2. Foreign Data Wrapper Callback Routines

56.3. Foreign Data Wrapper Helper Functions

56.4. Foreign Data Wrapper Query Planning

56.5. Row Locking in Foreign Data Wrappers

57. Writing a Table Sampling Method

57.1. Sampling Method Support Functions

58. Writing a Custom Scan Provider

58.1. Creating Custom Scan Paths

58.2. Creating Custom Scan Plans

58.3. Executing Custom Scans

59. Genetic Query Optimizer

59.1. Query Handling as a Complex Optimization Problem

59.2. Genetic Algorithms

59.3. Genetic Query Optimization (GEQO) in PostgreSQL

59.4. Further Reading

60. Table Access Method Interface Definition

61. Index Access Method Interface Definition

61.1. Basic API Structure for Indexes

61.2. Index Access Method Functions

61.3. Index Scanning

61.4. Index Locking Considerations

61.5. Index Uniqueness Checks

61.6. Index Cost Estimation Functions

62. Generic WAL Records

63. B-Tree Indexes

63.1. Introduction

63.2. Behavior of B-Tree Operator Classes

63.3. B-Tree Support Functions

63.4. Implementation

64. GiST Indexes

64.1. Introduction

64.2. Built-in Operator Classes

64.3. Extensibility

64.4. Implementation

64.5. Examples

65. SP-GiST Indexes

65.1. Introduction

65.2. Built-in Operator Classes

65.3. Extensibility

65.4. Implementation

65.5. Examples

66. GIN Indexes

66.1. Introduction

66.2. Built-in Operator Classes

66.3. Extensibility

66.4. Implementation

66.5. GIN Tips and Tricks

66.6. Limitations

66.7. Examples

67. BRIN Indexes

67.1. Introduction

67.2. Built-in Operator Classes

67.3. Extensibility

68. Hash Indexes

68.1. Overview

68.2. Implementation

69. Database Physical Storage

69.1. Database File Layout

69.2. TOAST

69.3. Free Space Map

69.4. Visibility Map

69.5. The Initialization Fork

69.6. Database Page Layout

69.7. Heap-Only Tuples (HOT)

70. System Catalog Declarations and Initial Contents

70.1. System Catalog Declaration Rules

70.2. System Catalog Initial Data

70.3. BKI File Format

70.4. BKI Commands

70.5. Structure of the Bootstrap BKI File

70.6. BKI Example

71. How the Planner Uses Statistics

71.1. Row Estimation Examples

71.2. Multivariate Statistics Examples

71.3. Planner Statistics and Security