30th September 2021: PostgreSQL 14 Released!
Supported Versions: Current (14) / 13 / 12 / 11 / 10 / 9.6
Development Versions: devel
Unsupported versions: 9.5 / 9.4 / 9.3 / 9.2 / 9.1 / 9.0 / 8.4 / 8.3 / 8.2 / 8.1 / 8.0 / 7.4

Part VII. Internals

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

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_policy
52.38. pg_proc
52.39. pg_publication
52.40. pg_publication_rel
52.41. pg_range
52.42. pg_replication_origin
52.43. pg_rewrite
52.44. pg_seclabel
52.45. pg_sequence
52.46. pg_shdepend
52.47. pg_shdescription
52.48. pg_shseclabel
52.49. pg_statistic
52.50. pg_statistic_ext
52.51. pg_statistic_ext_data
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_backend_memory_contexts
52.68. pg_config
52.69. pg_cursors
52.70. pg_file_settings
52.71. pg_group
52.72. pg_hba_file_rules
52.73. pg_indexes
52.74. pg_locks
52.75. pg_matviews
52.76. pg_policies
52.77. pg_prepared_statements
52.78. pg_prepared_xacts
52.79. pg_publication_tables
52.80. pg_replication_origin_status
52.81. pg_replication_slots
52.82. pg_roles
52.83. pg_rules
52.84. pg_seclabels
52.85. pg_sequences
52.86. pg_settings
52.87. pg_shadow
52.88. pg_shmem_allocations
52.89. pg_stats
52.90. pg_stats_ext
52.91. pg_stats_ext_exprs
52.92. pg_tables
52.93. pg_timezone_abbrevs
52.94. pg_timezone_names
52.95. pg_user
52.96. pg_user_mappings
52.97. 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. 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. Generic WAL Records
64. B-Tree Indexes
64.1. Introduction
64.2. Behavior of B-Tree Operator Classes
64.3. B-Tree Support Functions
64.4. Implementation
65. GiST Indexes
65.1. Introduction
65.2. Built-in Operator Classes
65.3. Extensibility
65.4. Implementation
65.5. Examples
66. SP-GiST Indexes
66.1. Introduction
66.2. Built-in Operator Classes
66.3. Extensibility
66.4. Implementation
66.5. Examples
67. GIN Indexes
67.1. Introduction
67.2. Built-in Operator Classes
67.3. Extensibility
67.4. Implementation
67.5. GIN Tips and Tricks
67.6. Limitations
67.7. Examples
68. BRIN Indexes
68.1. Introduction
68.2. Built-in Operator Classes
68.3. Extensibility
69. Hash Indexes
69.1. Overview
69.2. Implementation
70. Database Physical Storage
70.1. Database File Layout
70.2. TOAST
70.3. Free Space Map
70.4. Visibility Map
70.5. The Initialization Fork
70.6. Database Page Layout
71. System Catalog Declarations and Initial Contents
71.1. System Catalog Declaration Rules
71.2. System Catalog Initial Data
71.3. BKI File Format
71.4. BKI Commands
71.5. Structure of the Bootstrap BKI File
71.6. BKI Example
72. How the Planner Uses Statistics
72.1. Row Estimation Examples
72.2. Multivariate Statistics Examples
72.3. Planner Statistics and Security
73. Backup Manifest Format
73.1. Backup Manifest Top-level Object
73.2. Backup Manifest File Object
73.3. Backup Manifest WAL Range Object

Submit correction

If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.