# PostgreSQL 15 → 16 GUC 差异

> PG15 与 PG16 之间新增、boot 默认值变化和移除的核心配置参数。
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> [!NOTE]
> **Fact。** 实测在档数从 355 变为 364；新增 14、boot 默认值变化 2、移除 5。

## 新增参数 {#added}

| 参数 | 类型 | Context | Boot 默认值 | 分类 |
| --- | --- | --- | --- | --- |
| [`createrole_self_grant`](/zh/parameters/createrole-self-grant/) | `string` | `user` | `""` (empty string) | Client Connection Defaults / Statement Behavior |
| [`debug_io_direct`](/zh/parameters/debug-io-direct/) | `string` | `postmaster` | `""` (empty string) | Developer Options |
| [`debug_logical_replication_streaming`](/zh/parameters/debug-logical-replication-streaming/) | `enum` | `user` | `buffered` | Developer Options |
| [`debug_parallel_query`](/zh/parameters/debug-parallel-query/) | `enum` | `user` | `off` | Developer Options |
| [`enable_presorted_aggregate`](/zh/parameters/enable-presorted-aggregate/) | `bool` | `user` | `on` | Query Tuning / Planner Method Configuration |
| [`file_extend_method`](/zh/parameters/file-extend-method/) | `enum` | `sighup` | `posix_fallocate` | Resource Usage / Disk |
| [`gss_accept_delegation`](/zh/parameters/gss-accept-delegation/) | `bool` | `sighup` | `off` | Connections and Authentication / Authentication |
| [`icu_validation_level`](/zh/parameters/icu-validation-level/) | `enum` | `user` | `warning` | Client Connection Defaults / Locale and Formatting |
| [`max_parallel_apply_workers_per_subscription`](/zh/parameters/max-parallel-apply-workers-per-subscription/) | `integer` | `sighup` | `2` | Replication / Subscribers |
| [`reserved_connections`](/zh/parameters/reserved-connections/) | `integer` | `postmaster` | `0` | Connections and Authentication / Connection Settings |
| [`scram_iterations`](/zh/parameters/scram-iterations/) | `integer` | `user` | `4096` | Connections and Authentication / Authentication |
| [`send_abort_for_crash`](/zh/parameters/send-abort-for-crash/) | `bool` | `sighup` | `off` | Developer Options |
| [`send_abort_for_kill`](/zh/parameters/send-abort-for-kill/) | `bool` | `sighup` | `off` | Developer Options |
| [`vacuum_buffer_usage_limit`](/zh/parameters/vacuum-buffer-usage-limit/) | `integer` | `user` | `256 kB` (256 KiB) | Resource Usage / Memory |
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## Boot 默认值变化 {#default-changes}

| 参数 | PG15 | PG16 | 分类 |
| --- | --- | --- | --- |
| [`server_version`](/zh/parameters/server-version/) | `15.19 (Debian 15.19-1.pgdg13+2)` | `16.15 (Debian 16.15-1.pgdg13+2)` | Preset Options |
| [`server_version_num`](/zh/parameters/server-version-num/) | `150019` | `160015` | Preset Options |
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## 移除参数 {#removed}

| 参数 | 最后类型 | Context | 最后 Boot 默认值 | 分类 |
| --- | --- | --- | --- | --- |
| [`force_parallel_mode`](/zh/parameters/force-parallel-mode/) | `enum` | `user` | `off` | Developer Options |
| [`lc_collate`](/zh/parameters/lc-collate/) | `string` | `internal` | `C` | Preset Options |
| [`lc_ctype`](/zh/parameters/lc-ctype/) | `string` | `internal` | `C` | Preset Options |
| [`promote_trigger_file`](/zh/parameters/promote-trigger-file/) | `string` | `sighup` | `""` (empty string) | Replication / Standby Servers |
| [`vacuum_defer_cleanup_age`](/zh/parameters/vacuum-defer-cleanup-age/) | `integer` | `sighup` | `0` | Replication / Primary Server |
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## 计算方法 {#method}

三张清单直接比较固定环境中的 PG15 与 PG16 `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。

- [机器可读差异数据](/data/diffs.json)
- [完整 GUC JSONL](/data/guc.jsonl)