Part VII. Internals

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

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_partitioned_table
53.37. pg_policy
53.38. pg_proc
53.39. pg_publication
53.40. pg_publication_namespace
53.41. pg_publication_rel
53.42. pg_range
53.43. pg_replication_origin
53.44. pg_rewrite
53.45. pg_seclabel
53.46. pg_sequence
53.47. pg_shdepend
53.48. pg_shdescription
53.49. pg_shseclabel
53.50. pg_statistic
53.51. pg_statistic_ext
53.52. pg_statistic_ext_data
53.53. pg_subscription
53.54. pg_subscription_rel
53.55. pg_tablespace
53.56. pg_transform
53.57. pg_trigger
53.58. pg_ts_config
53.59. pg_ts_config_map
53.60. pg_ts_dict
53.61. pg_ts_parser
53.62. pg_ts_template
53.63. pg_type
53.64. pg_user_mapping
53.65. System Views
53.66. pg_available_extensions
53.67. pg_available_extension_versions
53.68. pg_backend_memory_contexts
53.69. pg_config
53.70. pg_cursors
53.71. pg_file_settings
53.72. pg_group
53.73. pg_hba_file_rules
53.74. pg_indexes
53.75. pg_locks
53.76. pg_matviews
53.77. pg_policies
53.78. pg_prepared_statements
53.79. pg_prepared_xacts
53.80. pg_publication_tables
53.81. pg_replication_origin_status
53.82. pg_replication_slots
53.83. pg_roles
53.84. pg_rules
53.85. pg_seclabels
53.86. pg_sequences
53.87. pg_settings
53.88. pg_shadow
53.89. pg_shmem_allocations
53.90. pg_stats
53.91. pg_stats_ext
53.92. pg_stats_ext_exprs
53.93. pg_tables
53.94. pg_timezone_abbrevs
53.95. pg_timezone_names
53.96. pg_user
53.97. pg_user_mappings
53.98. pg_views
54. Frontend/Backend Protocol
54.1. Overview
54.2. Message Flow
54.3. SASL Authentication
54.4. Streaming Replication Protocol
54.5. Logical Streaming Replication Protocol
54.6. Message Data Types
54.7. Message Formats
54.8. Error and Notice Message Fields
54.9. Logical Replication Message Formats
54.10. Summary of Changes since Protocol 2.0
55. PostgreSQL Coding Conventions
55.1. Formatting
55.2. Reporting Errors Within the Server
55.3. Error Message Style Guide
55.4. Miscellaneous Coding Conventions
56. Native Language Support
56.1. For the Translator
56.2. For the Programmer
57. Writing a Procedural Language Handler
58. Writing a Foreign Data Wrapper
58.1. Foreign Data Wrapper Functions
58.2. Foreign Data Wrapper Callback Routines
58.3. Foreign Data Wrapper Helper Functions
58.4. Foreign Data Wrapper Query Planning
58.5. Row Locking in Foreign Data Wrappers
59. Writing a Table Sampling Method
59.1. Sampling Method Support Functions
60. Writing a Custom Scan Provider
60.1. Creating Custom Scan Paths
60.2. Creating Custom Scan Plans
60.3. Executing Custom Scans
61. Genetic Query Optimizer
61.1. Query Handling as a Complex Optimization Problem
61.2. Genetic Algorithms
61.3. Genetic Query Optimization (GEQO) in PostgreSQL
61.4. Further Reading
62. Table Access Method Interface Definition
63. Index Access Method Interface Definition
63.1. Basic API Structure for Indexes
63.2. Index Access Method Functions
63.3. Index Scanning
63.4. Index Locking Considerations
63.5. Index Uniqueness Checks
63.6. Index Cost Estimation Functions
64. Generic WAL Records
65. B-Tree Indexes
65.1. Introduction
65.2. Behavior of B-Tree Operator Classes
65.3. B-Tree Support Functions
65.4. Implementation
66. GiST Indexes
66.1. Introduction
66.2. Built-in Operator Classes
66.3. Extensibility
66.4. Implementation
66.5. Examples
67. SP-GiST Indexes
67.1. Introduction
67.2. Built-in Operator Classes
67.3. Extensibility
67.4. Implementation
67.5. Examples
68. GIN Indexes
68.1. Introduction
68.2. Built-in Operator Classes
68.3. Extensibility
68.4. Implementation
68.5. GIN Tips and Tricks
68.6. Limitations
68.7. Examples
69. BRIN Indexes
69.1. Introduction
69.2. Built-in Operator Classes
69.3. Extensibility
70. Hash Indexes
70.1. Overview
70.2. Implementation
71. Database Physical Storage
71.1. Database File Layout
71.2. TOAST
71.3. Free Space Map
71.4. Visibility Map
71.5. The Initialization Fork
71.6. Database Page Layout
72. System Catalog Declarations and Initial Contents
72.1. System Catalog Declaration Rules
72.2. System Catalog Initial Data
72.3. BKI File Format
72.4. BKI Commands
72.5. Structure of the Bootstrap BKI File
72.6. BKI Example
73. How the Planner Uses Statistics
73.1. Row Estimation Examples
73.2. Multivariate Statistics Examples
73.3. Planner Statistics and Security
74. Backup Manifest Format
74.1. Backup Manifest Top-level Object
74.2. Backup Manifest File Object
74.3. Backup Manifest WAL Range Object