Part VII. Internals

Table of Contents

51. Overview of PostgreSQL Internals

51.1. The Path of a Query

51.2. How Connections are Established

51.3. The Parser Stage

51.4. The PostgreSQL Rule System

51.5. Planner/Optimizer

51.6. Executor

52. System Catalogs

52.1. Overview

52.2. pg_aggregate

52.3. pg_am

52.4. pg_amop

52.5. pg_amproc

52.6. pg_attrdef

52.7. pg_attribute

52.8. pg_authid

52.9. pg_auth_members

52.10. pg_cast

52.11. pg_class

52.12. pg_collation

52.13. pg_constraint

52.14. pg_conversion

52.15. pg_database

52.16. pg_db_role_setting

52.17. pg_default_acl

52.18. pg_depend

52.19. pg_description

52.20. pg_enum

52.21. pg_event_trigger

52.22. pg_extension

52.23. pg_foreign_data_wrapper

52.24. pg_foreign_server

52.25. pg_foreign_table

52.26. pg_index

52.27. pg_inherits

52.28. pg_init_privs

52.29. pg_language

52.30. pg_largeobject

52.31. pg_largeobject_metadata

52.32. pg_namespace

52.33. pg_opclass

52.34. pg_operator

52.35. pg_opfamily

52.36. pg_partitioned_table

52.37. pg_pltemplate

52.38. pg_policy

52.39. pg_proc

52.40. pg_publication

52.41. pg_publication_rel

52.42. pg_range

52.43. pg_replication_origin

52.44. pg_rewrite

52.45. pg_seclabel

52.46. pg_sequence

52.47. pg_shdepend

52.48. pg_shdescription

52.49. pg_shseclabel

52.50. pg_statistic

52.51. pg_statistic_ext

52.52. pg_subscription

52.53. pg_subscription_rel

52.54. pg_tablespace

52.55. pg_transform

52.56. pg_trigger

52.57. pg_ts_config

52.58. pg_ts_config_map

52.59. pg_ts_dict

52.60. pg_ts_parser

52.61. pg_ts_template

52.62. pg_type

52.63. pg_user_mapping

52.64. System Views

52.65. pg_available_extensions

52.66. pg_available_extension_versions

52.67. pg_config

52.68. pg_cursors

52.69. pg_file_settings

52.70. pg_group

52.71. pg_hba_file_rules

52.72. pg_indexes

52.73. pg_locks

52.74. pg_matviews

52.75. pg_policies

52.76. pg_prepared_statements

52.77. pg_prepared_xacts

52.78. pg_publication_tables

52.79. pg_replication_origin_status

52.80. pg_replication_slots

52.81. pg_roles

52.82. pg_rules

52.83. pg_seclabels

52.84. pg_sequences

52.85. pg_settings

52.86. pg_shadow

52.87. pg_stats

52.88. pg_tables

52.89. pg_timezone_abbrevs

52.90. pg_timezone_names

52.91. pg_user

52.92. pg_user_mappings

52.93. pg_views

53. Frontend/Backend Protocol

53.1. Overview

53.2. Message Flow

53.3. SASL Authentication

53.4. Streaming Replication Protocol

53.5. Logical Streaming Replication Protocol

53.6. Message Data Types

53.7. Message Formats

53.8. Error and Notice Message Fields

53.9. Logical Replication Message Formats

53.10. Summary of Changes since Protocol 2.0

54. PostgreSQL Coding Conventions

54.1. Formatting

54.2. Reporting Errors Within the Server

54.3. Error Message Style Guide

54.4. Miscellaneous Coding Conventions

55. Native Language Support

55.1. For the Translator

55.2. For the Programmer

56. Writing A Procedural Language Handler

57. Writing A Foreign Data Wrapper

57.1. Foreign Data Wrapper Functions

57.2. Foreign Data Wrapper Callback Routines

57.3. Foreign Data Wrapper Helper Functions

57.4. Foreign Data Wrapper Query Planning

57.5. Row Locking in Foreign Data Wrappers

58. Writing A Table Sampling Method

58.1. Sampling Method Support Functions

59. Writing A Custom Scan Provider

59.1. Creating Custom Scan Paths

59.2. Creating Custom Scan Plans

59.3. Executing Custom Scans

60. Genetic Query Optimizer

60.1. Query Handling as a Complex Optimization Problem

60.2. Genetic Algorithms

60.3. Genetic Query Optimization (GEQO) in PostgreSQL

60.4. Further Reading

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