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_parameter_acl

51.37. pg_partitioned_table

51.38. pg_policy

51.39. pg_proc

51.40. pg_publication

51.41. pg_publication_namespace

51.42. pg_publication_rel

51.43. pg_range

51.44. pg_replication_origin

51.45. pg_rewrite

51.46. pg_seclabel

51.47. pg_sequence

51.48. pg_shdepend

51.49. pg_shdescription

51.50. pg_shseclabel

51.51. pg_statistic

51.52. pg_statistic_ext

51.53. pg_statistic_ext_data

51.54. pg_subscription

51.55. pg_subscription_rel

51.56. pg_tablespace

51.57. pg_transform

51.58. pg_trigger

51.59. pg_ts_config

51.60. pg_ts_config_map

51.61. pg_ts_dict

51.62. pg_ts_parser

51.63. pg_ts_template

51.64. pg_type

51.65. pg_user_mapping

52. System Views

52.1. Overview

52.2. pg_available_extensions

52.3. pg_available_extension_versions

52.4. pg_backend_memory_contexts

52.5. pg_config

52.6. pg_cursors

52.7. pg_file_settings

52.8. pg_group

52.9. pg_hba_file_rules

52.10. pg_ident_file_mappings

52.11. pg_indexes

52.12. pg_locks

52.13. pg_matviews

52.14. pg_policies

52.15. pg_prepared_statements

52.16. pg_prepared_xacts

52.17. pg_publication_tables

52.18. pg_replication_origin_status

52.19. pg_replication_slots

52.20. pg_roles

52.21. pg_rules

52.22. pg_seclabels

52.23. pg_sequences

52.24. pg_settings

52.25. pg_shadow

52.26. pg_shmem_allocations

52.27. pg_stats

52.28. pg_stats_ext

52.29. pg_stats_ext_exprs

52.30. pg_tables

52.31. pg_timezone_abbrevs

52.32. pg_timezone_names

52.33. pg_user

52.34. pg_user_mappings

52.35. pg_views

52.36. pg_wait_events

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. Table Access Method Interface Definition

62. Index Access Method Interface Definition

62.1. Basic API Structure for Indexes

62.2. Index Access Method Functions

62.3. Index Scanning

62.4. Index Locking Considerations

62.5. Index Uniqueness Checks

62.6. Index Cost Estimation Functions

63. Write Ahead Logging for Extensions

63.1. Generic WAL Records

63.2. Custom WAL Resource Managers

64. Built-in Index Access Methods

64.1. B-Tree Indexes

64.2. GiST Indexes

64.3. SP-GiST Indexes

64.4. GIN Indexes

64.5. BRIN Indexes

64.6. Hash Indexes

65. Database Physical Storage

65.1. Database File Layout

65.2. TOAST

65.3. Free Space Map

65.4. Visibility Map

65.5. The Initialization Fork

65.6. Database Page Layout

65.7. Heap-Only Tuples (HOT)

66. Transaction Processing

66.1. Transactions and Identifiers

66.2. Transactions and Locking

66.3. Subtransactions

66.4. Two-Phase Transactions

67. System Catalog Declarations and Initial Contents

67.1. System Catalog Declaration Rules

67.2. System Catalog Initial Data

67.3. BKI File Format

67.4. BKI Commands

67.5. Structure of the Bootstrap BKI File

67.6. BKI Example

68. How the Planner Uses Statistics

68.1. Row Estimation Examples

68.2. Multivariate Statistics Examples

68.3. Planner Statistics and Security

69. Backup Manifest Format

69.1. Backup Manifest Top-level Object

69.2. Backup Manifest File Object

69.3. Backup Manifest WAL Range Object