# PostgreSQL 9.4 → 9.5 GUC 差异

> PG9.4 与 PG9.5 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 240 变为 249；新增 11、boot 默认值变化 3、移除 2。

## 新增参数 {#added}

| 参数 | 类型 | Context | Boot 默认值 | 分类 |
| --- | --- | --- | --- | --- |
| [`cluster_name`](/zh/parameters/cluster-name/) | `string` | `postmaster` | `""` (empty string) | Process Title |
| [`extension_destdir`](/zh/parameters/extension-destdir/) | `string` | `superuser` | `""` (empty string) | File Locations |
| [`gin_pending_list_limit`](/zh/parameters/gin-pending-list-limit/) | `integer` | `user` | `4096 kB` (4 MiB) | Client Connection Defaults / Statement Behavior |
| [`log_replication_commands`](/zh/parameters/log-replication-commands/) | `bool` | `superuser` | `off` | Reporting and Logging / What to Log |
| [`max_wal_size`](/zh/parameters/max-wal-size/) | `integer` | `sighup` | `64 16MB` (1 GiB (64 × 16MB)) | Write-Ahead Log / Checkpoints |
| [`min_wal_size`](/zh/parameters/min-wal-size/) | `integer` | `sighup` | `5 16MB` (80 MiB (5 × 16MB)) | Write-Ahead Log / Checkpoints |
| [`operator_precedence_warning`](/zh/parameters/operator-precedence-warning/) | `bool` | `user` | `off` | Version and Platform Compatibility / Previous PostgreSQL Versions |
| [`row_security`](/zh/parameters/row-security/) | `bool` | `user` | `on` | Connections and Authentication / Security and Authentication |
| [`track_commit_timestamp`](/zh/parameters/track-commit-timestamp/) | `bool` | `postmaster` | `off` | Replication |
| [`wal_compression`](/zh/parameters/wal-compression/) | `bool` | `superuser` | `off` | Write-Ahead Log / Settings |
| [`wal_retrieve_retry_interval`](/zh/parameters/wal-retrieve-retry-interval/) | `integer` | `sighup` | `5000 ms` (5 s) | Replication / Standby Servers |
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## Boot 默认值变化 {#default-changes}

| 参数 | PG9.4 | PG9.5 | 分类 |
| --- | --- | --- | --- |
| [`search_path`](/zh/parameters/search-path/) | `"$user",public` | `"$user", public` | Client Connection Defaults / Statement Behavior |
| [`server_version`](/zh/parameters/server-version/) | `9.4.26` | `9.5.25` | Preset Options |
| [`server_version_num`](/zh/parameters/server-version-num/) | `90426` | `90525` | 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 |
| --- | --- | --- | --- | --- |
| [`checkpoint_segments`](/zh/parameters/checkpoint-segments/) | `integer` | `sighup` | `3` | Write-Ahead Log / Checkpoints |
| [`ssl_renegotiation_limit`](/zh/parameters/ssl-renegotiation-limit/) | `integer` | `user` | `0 kB` (0 B) | Connections and Authentication / Security and Authentication |
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## 计算方法 {#method}

三张清单直接比较固定环境中的 PG9.4 与 PG9.5 `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)