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PostgreSQL 9.5.25 Documentation
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VII. Internals

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

Table of Contents
48. Overview of PostgreSQL Internals
48.1. The Path of a Query
48.2. How Connections are Established
48.3. The Parser Stage
48.4. The PostgreSQL Rule System
48.5. Planner/Optimizer
48.6. Executor
49. System Catalogs
49.1. Overview
49.2. pg_aggregate
49.3. pg_am
49.4. pg_amop
49.5. pg_amproc
49.6. pg_attrdef
49.7. pg_attribute
49.8. pg_authid
49.9. pg_auth_members
49.10. pg_cast
49.11. pg_class
49.12. pg_collation
49.13. pg_constraint
49.14. pg_conversion
49.15. pg_database
49.16. pg_db_role_setting
49.17. pg_default_acl
49.18. pg_depend
49.19. pg_description
49.20. pg_enum
49.21. pg_event_trigger
49.22. pg_extension
49.23. pg_foreign_data_wrapper
49.24. pg_foreign_server
49.25. pg_foreign_table
49.26. pg_index
49.27. pg_inherits
49.28. pg_language
49.29. pg_largeobject
49.30. pg_largeobject_metadata
49.31. pg_namespace
49.32. pg_opclass
49.33. pg_operator
49.34. pg_opfamily
49.35. pg_pltemplate
49.36. pg_policy
49.37. pg_proc
49.38. pg_range
49.39. pg_replication_origin
49.40. pg_rewrite
49.41. pg_seclabel
49.42. pg_shdepend
49.43. pg_shdescription
49.44. pg_shseclabel
49.45. pg_statistic
49.46. pg_tablespace
49.47. pg_transform
49.48. pg_trigger
49.49. pg_ts_config
49.50. pg_ts_config_map
49.51. pg_ts_dict
49.52. pg_ts_parser
49.53. pg_ts_template
49.54. pg_type
49.55. pg_user_mapping
49.56. System Views
49.57. pg_available_extensions
49.58. pg_available_extension_versions
49.59. pg_cursors
49.60. pg_file_settings
49.61. pg_group
49.62. pg_indexes
49.63. pg_locks
49.64. pg_matviews
49.65. pg_policies
49.66. pg_prepared_statements
49.67. pg_prepared_xacts
49.68. pg_replication_origin_status
49.69. pg_replication_slots
49.70. pg_roles
49.71. pg_rules
49.72. pg_seclabels
49.73. pg_settings
49.74. pg_shadow
49.75. pg_stats
49.76. pg_tables
49.77. pg_timezone_abbrevs
49.78. pg_timezone_names
49.79. pg_user
49.80. pg_user_mappings
49.81. pg_views
50. Frontend/Backend Protocol
50.1. Overview
50.2. Message Flow
50.3. Streaming Replication Protocol
50.4. Message Data Types
50.5. Message Formats
50.6. Error and Notice Message Fields
50.7. Summary of Changes since Protocol 2.0
51. PostgreSQL Coding Conventions
51.1. Formatting
51.2. Reporting Errors Within the Server
51.3. Error Message Style Guide
52. Native Language Support
52.1. For the Translator
52.2. For the Programmer
53. Writing A Procedural Language Handler
54. Writing A Foreign Data Wrapper
54.1. Foreign Data Wrapper Functions
54.2. Foreign Data Wrapper Callback Routines
54.3. Foreign Data Wrapper Helper Functions
54.4. Foreign Data Wrapper Query Planning
54.5. Row Locking in Foreign Data Wrappers
55. Writing A Table Sampling Method
55.1. Sampling Method Support Functions
56. Writing A Custom Scan Provider
56.1. Creating Custom Scan Paths
56.2. Creating Custom Scan Plans
56.3. Executing Custom Scans
57. Genetic Query Optimizer
57.1. Query Handling as a Complex Optimization Problem
57.2. Genetic Algorithms
57.3. Genetic Query Optimization (GEQO) in PostgreSQL
57.4. Further Reading
58. Index Access Method Interface Definition
58.1. Catalog Entries for Indexes
58.2. Index Access Method Functions
58.3. Index Scanning
58.4. Index Locking Considerations
58.5. Index Uniqueness Checks
58.6. Index Cost Estimation Functions
59. GiST Indexes
59.1. Introduction
59.2. Built-in Operator Classes
59.3. Extensibility
59.4. Implementation
59.5. Examples
60. SP-GiST Indexes
60.1. Introduction
60.2. Built-in Operator Classes
60.3. Extensibility
60.4. Implementation
60.5. Examples
61. GIN Indexes
61.1. Introduction
61.2. Built-in Operator Classes
61.3. Extensibility
61.4. Implementation
61.5. GIN Tips and Tricks
61.6. Limitations
61.7. Examples
62. BRIN Indexes
62.1. Introduction
62.2. Built-in Operator Classes
62.3. Extensibility
63. Database Physical Storage
63.1. Database File Layout
63.2. TOAST
63.3. Free Space Map
63.4. Visibility Map
63.5. The Initialization Fork
63.6. Database Page Layout
64. BKI Backend Interface
64.1. BKI File Format
64.2. BKI Commands
64.3. Structure of the Bootstrap BKI File
64.4. Example
65. How the Planner Uses Statistics
65.1. Row Estimation Examples
65.2. Planner Statistics and Security
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