PostgreSQL 17 → 18 GUC 差异

PG17 与 PG18 之间新增、boot 默认值变化和移除的核心配置参数。

说明

Fact。 实测在档数从 380 变为 399；新增 21、boot 默认值变化 5、移除 2。

新增参数

参数	类型	Context	Boot 默认值	分类
`autovacuum_vacuum_max_threshold`	`integer`	`sighup`	`100000000`	Vacuuming / Automatic Vacuuming
`autovacuum_worker_slots`	`integer`	`postmaster`	`16`	Vacuuming / Automatic Vacuuming
`enable_distinct_reordering`	`bool`	`user`	`on`	Query Tuning / Planner Method Configuration
`enable_self_join_elimination`	`bool`	`user`	`on`	Query Tuning / Planner Method Configuration
`extension_control_path`	`string`	`superuser`	`$system`	Client Connection Defaults / Other Defaults
`file_copy_method`	`enum`	`user`	`copy`	Resource Usage / Disk
`idle_replication_slot_timeout`	`integer`	`sighup`	`0 s`	Replication / Sending Servers
`io_max_combine_limit`	`integer`	`postmaster`	`16 8kB` (128 KiB (16 × 8kB))	Resource Usage / I/O
`io_max_concurrency`	`integer`	`postmaster`	`-1`	Resource Usage / I/O
`io_method`	`enum`	`postmaster`	`worker`	Resource Usage / I/O
`io_workers`	`integer`	`sighup`	`3`	Resource Usage / I/O
`log_lock_failures`	`bool`	`superuser`	`off`	Reporting and Logging / What to Log
`max_active_replication_origins`	`integer`	`postmaster`	`10`	Replication / Subscribers
`md5_password_warnings`	`bool`	`user`	`on`	Connections and Authentication / Authentication
`num_os_semaphores`	`integer`	`internal`	`0`	Preset Options
`oauth_validator_libraries`	`string`	`sighup`	`""` (empty string)	Connections and Authentication / Authentication
`ssl_groups`	`string`	`sighup`	`X25519:prime256v1`	Connections and Authentication / SSL
`ssl_tls13_ciphers`	`string`	`sighup`	`""` (empty string)	Connections and Authentication / SSL
`track_cost_delay_timing`	`bool`	`superuser`	`off`	Statistics / Cumulative Query and Index Statistics
`vacuum_max_eager_freeze_failure_rate`	`real`	`user`	`0.03`	Vacuuming / Freezing
`vacuum_truncate`	`bool`	`user`	`on`	Vacuuming / Default Behavior

Boot 默认值变化

参数	PG17	PG18	分类
`effective_io_concurrency`	`1`	`16`	Resource Usage / I/O
`log_connections`	`off`	`""` (empty string)	Reporting and Logging / What to Log
`maintenance_io_concurrency`	`10`	`16`	Resource Usage / I/O
`server_version`	`17.11 (Debian 17.11-1.pgdg13+2)`	`18.6 (Debian 18.6-1.pgdg13+2)`	Preset Options
`server_version_num`	`170011`	`180006`	Preset Options

移除参数

参数	最后类型	Context	最后 Boot 默认值	分类
`extension_destdir`	`string`	`superuser`	`""` (empty string)	File Locations
`ssl_ecdh_curve`	`string`	`sighup`	`prime256v1`	Connections and Authentication / SSL

计算方法

三张清单直接比较固定环境中的 PG17 与 PG18 pg_settings 快照。默认值变化使用 boot_val 与 unit 的组合；setting 不参与判定，以免把 initdb 生成值误当作编译时默认值。