Supported Versions: Current (11) / 10 / 9.6 / 9.5 / 9.4
Development Versions: 12 / devel
Unsupported versions: 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

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_partitioned_table
51.37. pg_pltemplate
51.38. pg_policy
51.39. pg_proc
51.40. pg_publication
51.41. pg_publication_rel
51.42. pg_range
51.43. pg_replication_origin
51.44. pg_rewrite
51.45. pg_seclabel
51.46. pg_sequence
51.47. pg_shdepend
51.48. pg_shdescription
51.49. pg_shseclabel
51.50. pg_statistic
51.51. pg_statistic_ext
51.52. pg_subscription
51.53. pg_subscription_rel
51.54. pg_tablespace
51.55. pg_transform
51.56. pg_trigger
51.57. pg_ts_config
51.58. pg_ts_config_map
51.59. pg_ts_dict
51.60. pg_ts_parser
51.61. pg_ts_template
51.62. pg_type
51.63. pg_user_mapping
51.64. System Views
51.65. pg_available_extensions
51.66. pg_available_extension_versions
51.67. pg_config
51.68. pg_cursors
51.69. pg_file_settings
51.70. pg_group
51.71. pg_hba_file_rules
51.72. pg_indexes
51.73. pg_locks
51.74. pg_matviews
51.75. pg_policies
51.76. pg_prepared_statements
51.77. pg_prepared_xacts
51.78. pg_publication_tables
51.79. pg_replication_origin_status
51.80. pg_replication_slots
51.81. pg_roles
51.82. pg_rules
51.83. pg_seclabels
51.84. pg_sequences
51.85. pg_settings
51.86. pg_shadow
51.87. pg_stats
51.88. pg_tables
51.89. pg_timezone_abbrevs
51.90. pg_timezone_names
51.91. pg_user
51.92. pg_user_mappings
51.93. pg_views
52. Frontend/Backend Protocol
52.1. Overview
52.2. Message Flow
52.3. SASL Authentication
52.4. Streaming Replication Protocol
52.5. Logical Streaming Replication Protocol
52.6. Message Data Types
52.7. Message Formats
52.8. Error and Notice Message Fields
52.9. Logical Replication Message Formats
52.10. Summary of Changes since Protocol 2.0
53. PostgreSQL Coding Conventions
53.1. Formatting
53.2. Reporting Errors Within the Server
53.3. Error Message Style Guide
53.4. Miscellaneous Coding Conventions
54. Native Language Support
54.1. For the Translator
54.2. For the Programmer
55. Writing A Procedural Language Handler
56. Writing A Foreign Data Wrapper
56.1. Foreign Data Wrapper Functions
56.2. Foreign Data Wrapper Callback Routines
56.3. Foreign Data Wrapper Helper Functions
56.4. Foreign Data Wrapper Query Planning
56.5. Row Locking in Foreign Data Wrappers
57. Writing A Table Sampling Method
57.1. Sampling Method Support Functions
58. Writing A Custom Scan Provider
58.1. Creating Custom Scan Paths
58.2. Creating Custom Scan Plans
58.3. Executing Custom Scans
59. Genetic Query Optimizer
59.1. Query Handling as a Complex Optimization Problem
59.2. Genetic Algorithms
59.3. Genetic Query Optimization (GEQO) in PostgreSQL
59.4. Further Reading
60. Table Access Method Interface Definition
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. Database Physical Storage
68.1. Database File Layout
68.2. TOAST
68.3. Free Space Map
68.4. Visibility Map
68.5. The Initialization Fork
68.6. Database Page Layout
69. System Catalog Declarations and Initial Contents
69.1. System Catalog Declaration Rules
69.2. System Catalog Initial Data
69.3. BKI File Format
69.4. BKI Commands
69.5. Structure of the Bootstrap BKI File
69.6. BKI Example
70. How the Planner Uses Statistics
70.1. Row Estimation Examples
70.2. Multivariate Statistics Examples
70.3. Planner Statistics and Security