# PostgreSQL 9.0 → 9.1 GUC 差异

> PG9.0 与 PG9.1 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 207 变为 219；新增 12、boot 默认值变化 10、移除 0。

## 新增参数 {#added}

| 参数 | 类型 | Context | Boot 默认值 | 分类 |
| --- | --- | --- | --- | --- |
| [`default_transaction_deferrable`](/zh/parameters/default-transaction-deferrable/) | `bool` | `user` | `off` | Client Connection Defaults / Statement Behavior |
| [`exit_on_error`](/zh/parameters/exit-on-error/) | `bool` | `user` | `off` | Error Handling |
| [`hot_standby_feedback`](/zh/parameters/hot-standby-feedback/) | `bool` | `sighup` | `off` | Replication / Standby Servers |
| [`log_file_mode`](/zh/parameters/log-file-mode/) | `integer` | `sighup` | `384` | Reporting and Logging / Where to Log |
| [`max_pred_locks_per_transaction`](/zh/parameters/max-pred-locks-per-transaction/) | `integer` | `postmaster` | `64` | Lock Management |
| [`quote_all_identifiers`](/zh/parameters/quote-all-identifiers/) | `bool` | `user` | `off` | Version and Platform Compatibility / Previous PostgreSQL Versions |
| [`replication_timeout`](/zh/parameters/replication-timeout/) | `integer` | `sighup` | `60000 ms` (1 min) | Replication / Master Server |
| [`restart_after_crash`](/zh/parameters/restart-after-crash/) | `bool` | `sighup` | `on` | Error Handling |
| [`ssl_ciphers`](/zh/parameters/ssl-ciphers/) | `string` | `postmaster` | `ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH` | Connections and Authentication / Security and Authentication |
| [`synchronous_standby_names`](/zh/parameters/synchronous-standby-names/) | `string` | `sighup` | `""` (empty string) | Replication / Master Server |
| [`transaction_deferrable`](/zh/parameters/transaction-deferrable/) | `bool` | `user` | `off` | Client Connection Defaults / Statement Behavior |
| [`wal_receiver_status_interval`](/zh/parameters/wal-receiver-status-interval/) | `integer` | `sighup` | `10 s` | Replication / Standby Servers |
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## Boot 默认值变化 {#default-changes}

| 参数 | PG9.0 | PG9.1 | 分类 |
| --- | --- | --- | --- |
| [`TimeZone`](/zh/parameters/timezone/) | `UNKNOWN` | — (not set) | Client Connection Defaults / Locale and Formatting |
| [`krb_server_keyfile`](/zh/parameters/krb-server-keyfile/) | `""` (empty string) | `FILE:/etc/postgresql-common/krb5.keytab` | Connections and Authentication / Security and Authentication |
| [`log_timezone`](/zh/parameters/log-timezone/) | `UNKNOWN` | — (not set) | Reporting and Logging / What to Log |
| [`server_version`](/zh/parameters/server-version/) | `9.0.23` | `9.1.24` | Preset Options |
| [`server_version_num`](/zh/parameters/server-version-num/) | `90023` | `90124` | Preset Options |
| [`standard_conforming_strings`](/zh/parameters/standard-conforming-strings/) | `off` | `on` | Version and Platform Compatibility / Previous PostgreSQL Versions |
| [`timezone_abbreviations`](/zh/parameters/timezone-abbreviations/) | `UNKNOWN` | — (not set) | Client Connection Defaults / Locale and Formatting |
| [`transaction_isolation`](/zh/parameters/transaction-isolation/) | — (not set) | `default` | Client Connection Defaults / Statement Behavior |
| [`wal_buffers`](/zh/parameters/wal-buffers/) | `8 8kB` (64 KiB (8 × 8kB)) | `-1 8kB` | Write-Ahead Log / Settings |
| [`wal_sender_delay`](/zh/parameters/wal-sender-delay/) | `200 ms` | `1000 ms` (1 s) | Replication / Master Server |
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## 移除参数 {#removed}

| 参数 | 最后类型 | Context | 最后 Boot 默认值 | 分类 |
| --- | --- | --- | --- | --- |
| — | — | — | — | — |
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## 计算方法 {#method}

三张清单直接比较固定环境中的 PG9.0 与 PG9.1 `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)