# Parameters > Complete dossiers for all 447 core PostgreSQL configuration parameters observed from 9.0 through 19 Beta 3. --- This section contains all **447** core GUCs in the measured PostgreSQL 9.0–19 Beta 3 union: 419 remain in 19 Beta 3, 28 were removed during the interval, and 240 first appear after 9.0. Every dossier includes identity, lifecycle, default history, mechanism, tuning advice, Pigsty values, pitfalls, related entries, and sources. - [Complete JSONL export](/data/guc.jsonl) - [Adjacent-version diffs](/diff/) - [Pigsty default-delta atlas](/pigsty/) ## Categories {#categories} | Category | Parameters | | --- | ---: | | [Client Connection Defaults](/parameters/client-connection-defaults/) | 47 | | [Connections and Authentication](/parameters/connections-authentication/) | 45 | | [Customized Options](/parameters/customized-options/) | 1 | | [Developer Options](/parameters/developer-options/) | 27 | | [Error Handling](/parameters/error-handling/) | 4 | | [File Locations](/parameters/file-locations/) | 7 | | [Lock Management](/parameters/lock-management/) | 5 | | [Preset Options](/parameters/preset-options/) | 24 | | [Query Tuning](/parameters/query-tuning/) | 55 | | [Replication](/parameters/replication/) | 33 | | [Reporting and Logging](/parameters/reporting-logging/) | 47 | | [Resource Usage](/parameters/resource-usage/) | 51 | | [Statistics](/parameters/statistics/) | 14 | | [Vacuuming](/parameters/vacuuming/) | 34 | | [Version and Platform Compatibility](/parameters/version-platform-compatibility/) | 12 | | [Write-Ahead Log](/parameters/write-ahead-log/) | 41 | ## Boot defaults that changed {#default-changed} These parameters changed `boot_val` or `unit` during PostgreSQL 9.0–19 Beta 3: [`TimeZone`](/parameters/timezone/) · [`autovacuum_vacuum_cost_delay`](/parameters/autovacuum-vacuum-cost-delay/) · [`checkpoint_completion_target`](/parameters/checkpoint-completion-target/) · [`default_toast_compression`](/parameters/default-toast-compression/) · [`effective_cache_size`](/parameters/effective-cache-size/) · [`effective_io_concurrency`](/parameters/effective-io-concurrency/) · [`extra_float_digits`](/parameters/extra-float-digits/) · [`hash_mem_multiplier`](/parameters/hash-mem-multiplier/) · [`hot_standby`](/parameters/hot-standby/) · [`jit`](/parameters/jit/) · [`krb_server_keyfile`](/parameters/krb-server-keyfile/) · [`log_autovacuum_min_duration`](/parameters/log-autovacuum-min-duration/) · [`log_checkpoints`](/parameters/log-checkpoints/) · [`log_connections`](/parameters/log-connections/) · [`log_directory`](/parameters/log-directory/) · [`log_line_prefix`](/parameters/log-line-prefix/) · [`log_lock_waits`](/parameters/log-lock-waits/) · [`log_timezone`](/parameters/log-timezone/) · [`maintenance_io_concurrency`](/parameters/maintenance-io-concurrency/) · [`maintenance_work_mem`](/parameters/maintenance-work-mem/) · [`max_locks_per_transaction`](/parameters/max-locks-per-transaction/) · [`max_parallel_workers_per_gather`](/parameters/max-parallel-workers-per-gather/) · [`max_replication_slots`](/parameters/max-replication-slots/) · [`max_wal_senders`](/parameters/max-wal-senders/) · [`max_wal_size`](/parameters/max-wal-size/) · [`min_wal_size`](/parameters/min-wal-size/) · [`password_encryption`](/parameters/password-encryption/) · [`search_path`](/parameters/search-path/) · [`server_version`](/parameters/server-version/) · [`server_version_num`](/parameters/server-version-num/) · [`shared_buffers`](/parameters/shared-buffers/) · [`ssl_ciphers`](/parameters/ssl-ciphers/) · [`ssl_min_protocol_version`](/parameters/ssl-min-protocol-version/) · [`standard_conforming_strings`](/parameters/standard-conforming-strings/) · [`timezone_abbreviations`](/parameters/timezone-abbreviations/) · [`track_activity_query_size`](/parameters/track-activity-query-size/) · [`transaction_isolation`](/parameters/transaction-isolation/) · [`vacuum_buffer_usage_limit`](/parameters/vacuum-buffer-usage-limit/) · [`vacuum_cost_page_miss`](/parameters/vacuum-cost-page-miss/) · [`wal_buffers`](/parameters/wal-buffers/) · [`wal_level`](/parameters/wal-level/) · [`wal_segment_size`](/parameters/wal-segment-size/) · [`wal_sender_delay`](/parameters/wal-sender-delay/) · [`work_mem`](/parameters/work-mem/) ## Removed parameters {#removed} These parameters left `pg_settings` before PostgreSQL 19 Beta 3 and retain historical dossiers: [`checkpoint_segments`](/parameters/checkpoint-segments/) · [`custom_variable_classes`](/parameters/custom-variable-classes/) · [`db_user_namespace`](/parameters/db-user-namespace/) · [`default_with_oids`](/parameters/default-with-oids/) · [`escape_string_warning`](/parameters/escape-string-warning/) · [`extension_destdir`](/parameters/extension-destdir/) · [`force_parallel_mode`](/parameters/force-parallel-mode/) · [`io_workers`](/parameters/io-workers/) · [`krb_srvname`](/parameters/krb-srvname/) · [`lc_collate`](/parameters/lc-collate/) · [`lc_ctype`](/parameters/lc-ctype/) · [`min_parallel_relation_size`](/parameters/min-parallel-relation-size/) · [`old_snapshot_threshold`](/parameters/old-snapshot-threshold/) · [`operator_precedence_warning`](/parameters/operator-precedence-warning/) · [`promote_trigger_file`](/parameters/promote-trigger-file/) · [`replacement_sort_tuples`](/parameters/replacement-sort-tuples/) · [`replication_timeout`](/parameters/replication-timeout/) · [`silent_mode`](/parameters/silent-mode/) · [`sql_inheritance`](/parameters/sql-inheritance/) · [`ssl_ecdh_curve`](/parameters/ssl-ecdh-curve/) · [`ssl_renegotiation_limit`](/parameters/ssl-renegotiation-limit/) · [`stats_temp_directory`](/parameters/stats-temp-directory/) · [`trace_recovery_messages`](/parameters/trace-recovery-messages/) · [`unix_socket_directory`](/parameters/unix-socket-directory/) · [`vacuum_cleanup_index_scale_factor`](/parameters/vacuum-cleanup-index-scale-factor/) · [`vacuum_defer_cleanup_age`](/parameters/vacuum-defer-cleanup-age/) · [`wal_keep_segments`](/parameters/wal-keep-segments/) · [`wal_sender_delay`](/parameters/wal-sender-delay/) --- Section pages: - [Client Connection Defaults](/parameters/client-connection-defaults/): Complete dossiers for 47 core PostgreSQL settings in Client Connection Defaults. - [Connections and Authentication](/parameters/connections-authentication/): Complete dossiers for 45 core PostgreSQL settings in Connections and Authentication. - [Customized Options](/parameters/customized-options/): Complete dossiers for 1 core PostgreSQL settings in Customized Options. - [Developer Options](/parameters/developer-options/): Complete dossiers for 27 core PostgreSQL settings in Developer Options. - [Error Handling](/parameters/error-handling/): Complete dossiers for 4 core PostgreSQL settings in Error Handling. - [File Locations](/parameters/file-locations/): Complete dossiers for 7 core PostgreSQL settings in File Locations. - [Lock Management](/parameters/lock-management/): Complete dossiers for 5 core PostgreSQL settings in Lock Management. - [Preset Options](/parameters/preset-options/): Complete dossiers for 24 core PostgreSQL settings in Preset Options. - [Query Tuning](/parameters/query-tuning/): Complete dossiers for 55 core PostgreSQL settings in Query Tuning. - [Replication](/parameters/replication/): Complete dossiers for 33 core PostgreSQL settings in Replication. - [Reporting and Logging](/parameters/reporting-logging/): Complete dossiers for 47 core PostgreSQL settings in Reporting and Logging. - [Resource Usage](/parameters/resource-usage/): Complete dossiers for 51 core PostgreSQL settings in Resource Usage. - [Statistics](/parameters/statistics/): Complete dossiers for 14 core PostgreSQL settings in Statistics. - [Vacuuming](/parameters/vacuuming/): Complete dossiers for 34 core PostgreSQL settings in Vacuuming. - [Version and Platform Compatibility](/parameters/version-platform-compatibility/): Complete dossiers for 12 core PostgreSQL settings in Version and Platform Compatibility. - [Write-Ahead Log](/parameters/write-ahead-log/): Complete dossiers for 41 core PostgreSQL settings in Write-Ahead Log.