Chapter 51. System Catalogs

Table of Contents

51.1. Overview
51.2. lt_type_ext
51.3. pg_aggregate
51.4. pg_am
51.5. pg_amop
51.6. pg_amproc
51.7. pg_attrdef
51.8. pg_attribute
51.9. pg_authid
51.10. pg_auth_members
51.11. pg_cast
51.12. pg_class
51.13. pg_collation
51.14. pg_constraint
51.15. pg_conversion
51.16. pg_database
51.17. pg_db_role_setting
51.18. pg_default_acl
51.19. pg_depend
51.20. pg_description
51.21. pg_enum
51.22. pg_event_trigger
51.23. pg_extension
51.24. pg_foreign_data_wrapper
51.25. pg_foreign_server
51.26. pg_foreign_table
51.27. pg_index
51.28. pg_inherits
51.29. pg_init_privs
51.30. pg_language
51.31. pg_largeobject
51.32. pg_largeobject_metadata
51.33. pg_namespace
51.34. pg_opclass
51.35. pg_operator
51.36. pg_opfamily
51.37. pg_partitioned_table
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_statistic_ext_data
51.53. pg_subscription
51.54. pg_subscription_rel
51.55. pg_tablespace
51.56. pg_transform
51.57. pg_trigger
51.58. pg_ts_config
51.59. pg_ts_config_map
51.60. pg_ts_dict
51.61. pg_ts_parser
51.62. pg_ts_template
51.63. pg_type
51.64. pg_user_mapping
51.65. System Views
51.66. pg_available_extensions
51.67. pg_available_extension_versions
51.68. pg_config
51.69. pg_cursors
51.70. pg_file_settings
51.71. pg_group
51.72. pg_hba_file_rules
51.73. pg_indexes
51.74. pg_locks
51.75. pg_matviews
51.76. pg_policies
51.77. pg_prepared_statements
51.78. pg_prepared_xacts
51.79. pg_publication_tables
51.80. pg_replication_origin_status
51.81. pg_replication_slots
51.82. pg_roles
51.83. pg_rules
51.84. pg_seclabels
51.85. pg_sequences
51.86. pg_settings
51.87. pg_shadow
51.88. pg_shmem_allocations
51.89. pg_stats
51.90. pg_stats_ext
51.91. pg_tables
51.92. pg_timezone_abbrevs
51.93. pg_timezone_names
51.94. pg_user
51.95. pg_user_mappings
51.96. pg_views

The system catalogs are the place where a relational database management system stores schema metadata, such as information about tables and columns, and internal bookkeeping information. LightDB's system catalogs are regular tables. You can drop and recreate the tables, add columns, insert and update values, and severely mess up your system that way. Normally, one should not change the system catalogs by hand, there are normally SQL commands to do that. (For example, CREATE DATABASE inserts a row into the pg_database catalog — and actually creates the database on disk.) There are some exceptions for particularly esoteric operations, but many of those have been made available as SQL commands over time, and so the need for direct manipulation of the system catalogs is ever decreasing.