Part VII. Internals

Table of Contents

52. Overview of PostgreSQL Internals

52.1. The Path of a Query

52.2. How Connections Are Established

52.3. The Parser Stage

52.4. The PostgreSQL Rule System

52.5. Planner/Optimizer

52.6. Executor

53. System Catalogs

53.1. Overview

53.2. pg_aggregate

53.3. pg_am

53.4. pg_amop

53.5. pg_amproc

53.6. pg_attrdef

53.7. pg_attribute

53.8. pg_authid

53.9. pg_auth_members

53.10. pg_cast

53.11. pg_class

53.12. pg_collation

53.13. pg_constraint

53.14. pg_conversion

53.15. pg_database

53.16. pg_db_role_setting

53.17. pg_default_acl

53.18. pg_depend

53.19. pg_description

53.20. pg_enum

53.21. pg_event_trigger

53.22. pg_extension

53.23. pg_foreign_data_wrapper

53.24. pg_foreign_server

53.25. pg_foreign_table

53.26. pg_index

53.27. pg_inherits

53.28. pg_init_privs

53.29. pg_language

53.30. pg_largeobject

53.31. pg_largeobject_metadata

53.32. pg_namespace

53.33. pg_opclass

53.34. pg_operator

53.35. pg_opfamily

53.36. pg_parameter_acl

53.37. pg_partitioned_table

53.38. pg_policy

53.39. pg_proc

53.40. pg_publication

53.41. pg_publication_namespace

53.42. pg_publication_rel

53.43. pg_range

53.44. pg_replication_origin

53.45. pg_rewrite

53.46. pg_seclabel

53.47. pg_sequence

53.48. pg_shdepend

53.49. pg_shdescription

53.50. pg_shseclabel

53.51. pg_statistic

53.52. pg_statistic_ext

53.53. pg_statistic_ext_data

53.54. pg_subscription

53.55. pg_subscription_rel

53.56. pg_tablespace

53.57. pg_transform

53.58. pg_trigger

53.59. pg_ts_config

53.60. pg_ts_config_map

53.61. pg_ts_dict

53.62. pg_ts_parser

53.63. pg_ts_template

53.64. pg_type

53.65. pg_user_mapping

54. System Views

54.1. Overview

54.2. pg_available_extensions

54.3. pg_available_extension_versions

54.4. pg_backend_memory_contexts

54.5. pg_config

54.6. pg_cursors

54.7. pg_file_settings

54.8. pg_group

54.9. pg_hba_file_rules

54.10. pg_ident_file_mappings

54.11. pg_indexes

54.12. pg_locks

54.13. pg_matviews

54.14. pg_policies

54.15. pg_prepared_statements

54.16. pg_prepared_xacts

54.17. pg_publication_tables

54.18. pg_replication_origin_status

54.19. pg_replication_slots

54.20. pg_roles

54.21. pg_rules

54.22. pg_seclabels

54.23. pg_sequences

54.24. pg_settings

54.25. pg_shadow

54.26. pg_shmem_allocations

54.27. pg_stats

54.28. pg_stats_ext

54.29. pg_stats_ext_exprs

54.30. pg_tables

54.31. pg_timezone_abbrevs

54.32. pg_timezone_names

54.33. pg_user

54.34. pg_user_mappings

54.35. pg_views

55. Frontend/Backend Protocol

55.1. Overview

55.2. Message Flow

55.3. SASL Authentication

55.4. Streaming Replication Protocol

55.5. Logical Streaming Replication Protocol

55.6. Message Data Types

55.7. Message Formats

55.8. Error and Notice Message Fields

55.9. Logical Replication Message Formats

55.10. Summary of Changes since Protocol 2.0

56. PostgreSQL Coding Conventions

56.1. Formatting

56.2. Reporting Errors Within the Server

56.3. Error Message Style Guide

56.4. Miscellaneous Coding Conventions

57. Native Language Support

57.1. For the Translator

57.2. For the Programmer

58. Writing a Procedural Language Handler

59. Writing a Foreign Data Wrapper

59.1. Foreign Data Wrapper Functions

59.2. Foreign Data Wrapper Callback Routines

59.3. Foreign Data Wrapper Helper Functions

59.4. Foreign Data Wrapper Query Planning

59.5. Row Locking in Foreign Data Wrappers

60. Writing a Table Sampling Method

60.1. Sampling Method Support Functions

61. Writing a Custom Scan Provider

61.1. Creating Custom Scan Paths

61.2. Creating Custom Scan Plans

61.3. Executing Custom Scans

62. Genetic Query Optimizer

62.1. Query Handling as a Complex Optimization Problem

62.2. Genetic Algorithms

62.3. Genetic Query Optimization ( GEQO ) in PostgreSQL

62.4. Further Reading

63. Table Access Method Interface Definition

64. Index Access Method Interface Definition

64.1. Basic API Structure for Indexes

64.2. Index Access Method Functions

64.3. Index Scanning

64.4. Index Locking Considerations

64.5. Index Uniqueness Checks

64.6. Index Cost Estimation Functions

65. Generic WAL Records

66. Custom WAL Resource Managers

67. B-Tree Indexes

67.1. Introduction

67.2. Behavior of B-Tree Operator Classes

67.3. B-Tree Support Functions

67.4. Implementation

68. GiST Indexes

68.1. Introduction

68.2. Built-in Operator Classes

68.3. Extensibility

68.4. Implementation

68.5. Examples

69. SP-GiST Indexes

69.1. Introduction

69.2. Built-in Operator Classes

69.3. Extensibility

69.4. Implementation

69.5. Examples

70. GIN Indexes

70.1. Introduction

70.2. Built-in Operator Classes

70.3. Extensibility

70.4. Implementation

70.5. GIN Tips and Tricks

70.6. Limitations

70.7. Examples

71. BRIN Indexes

71.1. Introduction

71.2. Built-in Operator Classes

71.3. Extensibility

72. Hash Indexes

72.1. Overview

72.2. Implementation

73. Database Physical Storage

73.1. Database File Layout

73.2. TOAST

73.3. Free Space Map

73.4. Visibility Map

73.5. The Initialization Fork

73.6. Database Page Layout

73.7. Heap-Only Tuples ( HOT )

74. Transaction Processing

74.1. Transactions and Identifiers

74.2. Transactions and Locking

74.3. Subtransactions

74.4. Two-Phase Transactions

75. System Catalog Declarations and Initial Contents

75.1. System Catalog Declaration Rules

75.2. System Catalog Initial Data

75.3. BKI File Format

75.4. BKI Commands

75.5. Structure of the Bootstrap BKI File

75.6. BKI Example

76. How the Planner Uses Statistics

76.1. Row Estimation Examples

76.2. Multivariate Statistics Examples

76.3. Planner Statistics and Security

77. Backup Manifest Format

77.1. Backup Manifest Top-level Object

77.2. Backup Manifest File Object

77.3. Backup Manifest WAL Range Object