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PostgreSQL 9.6.24 Documentation
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VII. Internals

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

Table of Contents
49. Overview of PostgreSQL Internals
49.1. The Path of a Query
49.2. How Connections are Established
49.3. The Parser Stage
49.4. The PostgreSQL Rule System
49.5. Planner/Optimizer
49.6. Executor
50. System Catalogs
50.1. Overview
50.2. pg_aggregate
50.3. pg_am
50.4. pg_amop
50.5. pg_amproc
50.6. pg_attrdef
50.7. pg_attribute
50.8. pg_authid
50.9. pg_auth_members
50.10. pg_cast
50.11. pg_class
50.12. pg_collation
50.13. pg_constraint
50.14. pg_conversion
50.15. pg_database
50.16. pg_db_role_setting
50.17. pg_default_acl
50.18. pg_depend
50.19. pg_description
50.20. pg_enum
50.21. pg_event_trigger
50.22. pg_extension
50.23. pg_foreign_data_wrapper
50.24. pg_foreign_server
50.25. pg_foreign_table
50.26. pg_index
50.27. pg_inherits
50.28. pg_init_privs
50.29. pg_language
50.30. pg_largeobject
50.31. pg_largeobject_metadata
50.32. pg_namespace
50.33. pg_opclass
50.34. pg_operator
50.35. pg_opfamily
50.36. pg_pltemplate
50.37. pg_policy
50.38. pg_proc
50.39. pg_range
50.40. pg_replication_origin
50.41. pg_rewrite
50.42. pg_seclabel
50.43. pg_shdepend
50.44. pg_shdescription
50.45. pg_shseclabel
50.46. pg_statistic
50.47. pg_tablespace
50.48. pg_transform
50.49. pg_trigger
50.50. pg_ts_config
50.51. pg_ts_config_map
50.52. pg_ts_dict
50.53. pg_ts_parser
50.54. pg_ts_template
50.55. pg_type
50.56. pg_user_mapping
50.57. System Views
50.58. pg_available_extensions
50.59. pg_available_extension_versions
50.60. pg_config
50.61. pg_cursors
50.62. pg_file_settings
50.63. pg_group
50.64. pg_indexes
50.65. pg_locks
50.66. pg_matviews
50.67. pg_policies
50.68. pg_prepared_statements
50.69. pg_prepared_xacts
50.70. pg_replication_origin_status
50.71. pg_replication_slots
50.72. pg_roles
50.73. pg_rules
50.74. pg_seclabels
50.75. pg_settings
50.76. pg_shadow
50.77. pg_stats
50.78. pg_tables
50.79. pg_timezone_abbrevs
50.80. pg_timezone_names
50.81. pg_user
50.82. pg_user_mappings
50.83. pg_views
51. Frontend/Backend Protocol
51.1. Overview
51.2. Message Flow
51.3. Streaming Replication Protocol
51.4. Message Data Types
51.5. Message Formats
51.6. Error and Notice Message Fields
51.7. Summary of Changes since Protocol 2.0
52. PostgreSQL Coding Conventions
52.1. Formatting
52.2. Reporting Errors Within the Server
52.3. Error Message Style Guide
52.4. Miscellaneous Coding Conventions
53. Native Language Support
53.1. For the Translator
53.2. For the Programmer
54. Writing A Procedural Language Handler
55. Writing A Foreign Data Wrapper
55.1. Foreign Data Wrapper Functions
55.2. Foreign Data Wrapper Callback Routines
55.3. Foreign Data Wrapper Helper Functions
55.4. Foreign Data Wrapper Query Planning
55.5. Row Locking in Foreign Data Wrappers
56. Writing A Table Sampling Method
56.1. Sampling Method Support Functions
57. Writing A Custom Scan Provider
57.1. Creating Custom Scan Paths
57.2. Creating Custom Scan Plans
57.3. Executing Custom Scans
58. Genetic Query Optimizer
58.1. Query Handling as a Complex Optimization Problem
58.2. Genetic Algorithms
58.3. Genetic Query Optimization (GEQO) in PostgreSQL
58.4. Further Reading
59. Index Access Method Interface Definition
59.1. Basic API Structure for Indexes
59.2. Index Access Method Functions
59.3. Index Scanning
59.4. Index Locking Considerations
59.5. Index Uniqueness Checks
59.6. Index Cost Estimation Functions
60. Generic WAL Records
61. GiST Indexes
61.1. Introduction
61.2. Built-in Operator Classes
61.3. Extensibility
61.4. Implementation
61.5. Examples
62. SP-GiST Indexes
62.1. Introduction
62.2. Built-in Operator Classes
62.3. Extensibility
62.4. Implementation
62.5. Examples
63. GIN Indexes
63.1. Introduction
63.2. Built-in Operator Classes
63.3. Extensibility
63.4. Implementation
63.5. GIN Tips and Tricks
63.6. Limitations
63.7. Examples
64. BRIN Indexes
64.1. Introduction
64.2. Built-in Operator Classes
64.3. Extensibility
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
66. BKI Backend Interface
66.1. BKI File Format
66.2. BKI Commands
66.3. Structure of the Bootstrap BKI File
66.4. Example
67. How the Planner Uses Statistics
67.1. Row Estimation Examples
67.2. Planner Statistics and Security
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