# PostgreSQL 9.3 → 9.4 GUC 差异

> PG9.3 与 PG9.4 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 231 变为 240；新增 10、boot 默认值变化 6、移除 1。

## 新增参数 {#added}

| 参数 | 类型 | Context | Boot 默认值 | 分类 |
| --- | --- | --- | --- | --- |
| [`autovacuum_work_mem`](/zh/parameters/autovacuum-work-mem/) | `integer` | `sighup` | `-1 kB` | Resource Usage / Memory |
| [`data_sync_retry`](/zh/parameters/data-sync-retry/) | `bool` | `postmaster` | `off` | Error Handling |
| [`dynamic_shared_memory_type`](/zh/parameters/dynamic-shared-memory-type/) | `enum` | `postmaster` | `posix` | Resource Usage / Memory |
| [`huge_pages`](/zh/parameters/huge-pages/) | `enum` | `postmaster` | `try` | Resource Usage / Memory |
| [`max_replication_slots`](/zh/parameters/max-replication-slots/) | `integer` | `postmaster` | `0` | Replication / Sending Servers |
| [`max_worker_processes`](/zh/parameters/max-worker-processes/) | `integer` | `postmaster` | `8` | Resource Usage / Asynchronous Behavior |
| [`session_preload_libraries`](/zh/parameters/session-preload-libraries/) | `string` | `superuser` | `""` (empty string) | Client Connection Defaults / Shared Library Preloading |
| [`ssl_ecdh_curve`](/zh/parameters/ssl-ecdh-curve/) | `string` | `postmaster` | `prime256v1` | Connections and Authentication / Security and Authentication |
| [`ssl_prefer_server_ciphers`](/zh/parameters/ssl-prefer-server-ciphers/) | `bool` | `postmaster` | `on` | Connections and Authentication / Security and Authentication |
| [`wal_log_hints`](/zh/parameters/wal-log-hints/) | `bool` | `postmaster` | `off` | Write-Ahead Log / Settings |
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## Boot 默认值变化 {#default-changes}

| 参数 | PG9.3 | PG9.4 | 分类 |
| --- | --- | --- | --- |
| [`effective_cache_size`](/zh/parameters/effective-cache-size/) | `16384 8kB` (128 MiB (16384 × 8kB)) | `524288 8kB` (4 GiB (524288 × 8kB)) | Query Tuning / Planner Cost Constants |
| [`maintenance_work_mem`](/zh/parameters/maintenance-work-mem/) | `16384 kB` (16 MiB) | `65536 kB` (64 MiB) | Resource Usage / Memory |
| [`server_version`](/zh/parameters/server-version/) | `9.3.25` | `9.4.26` | Preset Options |
| [`server_version_num`](/zh/parameters/server-version-num/) | `90325` | `90426` | Preset Options |
| [`ssl_ciphers`](/zh/parameters/ssl-ciphers/) | `DEFAULT:!LOW:!EXP:!MD5:@STRENGTH` | `HIGH:MEDIUM:+3DES:!aNULL` | Connections and Authentication / Security and Authentication |
| [`work_mem`](/zh/parameters/work-mem/) | `1024 kB` (1 MiB) | `4096 kB` (4 MiB) | Resource Usage / Memory |
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## 移除参数 {#removed}

| 参数 | 最后类型 | Context | 最后 Boot 默认值 | 分类 |
| --- | --- | --- | --- | --- |
| [`krb_srvname`](/zh/parameters/krb-srvname/) | `string` | `sighup` | `postgres` | 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 PG9.3 与 PG9.4 `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)