# PostgreSQL 14 → 15 GUC diff

> Core configuration parameters added, removed, or changed in boot default between PostgreSQL 14 and 15.
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> [!NOTE]
> **Fact.** The measured inventory changes from 348 to 355 settings: 8 added, 6 boot-default changes, and 1 removed.

## Added parameters {#added}

| Parameter | Type | Context | Boot default | Category |
| --- | --- | --- | --- | --- |
| [`archive_library`](/parameters/archive-library/) | `string` | `sighup` | `""` (empty string) | Write-Ahead Log / Archiving |
| [`log_startup_progress_interval`](/parameters/log-startup-progress-interval/) | `integer` | `sighup` | `10000 ms` (10 s) | Reporting and Logging / When to Log |
| [`recovery_prefetch`](/parameters/recovery-prefetch/) | `enum` | `sighup` | `try` | Write-Ahead Log / Recovery |
| [`recursive_worktable_factor`](/parameters/recursive-worktable-factor/) | `real` | `user` | `10` | Query Tuning / Other Planner Options |
| [`shared_memory_size`](/parameters/shared-memory-size/) | `integer` | `internal` | `0 MB` (0 B) | Preset Options |
| [`shared_memory_size_in_huge_pages`](/parameters/shared-memory-size-in-huge-pages/) | `integer` | `internal` | `-1` | Preset Options |
| [`stats_fetch_consistency`](/parameters/stats-fetch-consistency/) | `enum` | `user` | `cache` | Statistics / Cumulative Query and Index Statistics |
| [`wal_decode_buffer_size`](/parameters/wal-decode-buffer-size/) | `integer` | `postmaster` | `524288 B` (512 KiB) | Write-Ahead Log / Recovery |
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## Boot-default changes {#default-changes}

| Parameter | PG14 | PG15 | Category |
| --- | --- | --- | --- |
| [`hash_mem_multiplier`](/parameters/hash-mem-multiplier/) | `1` | `2` | Resource Usage / Memory |
| [`log_autovacuum_min_duration`](/parameters/log-autovacuum-min-duration/) | `-1 ms` | `600000 ms` (10 min) | Reporting and Logging / What to Log |
| [`log_checkpoints`](/parameters/log-checkpoints/) | `off` | `on` | Reporting and Logging / What to Log |
| [`server_version`](/parameters/server-version/) | `14.24 (Debian 14.24-1.pgdg13+2)` | `15.19 (Debian 15.19-1.pgdg13+2)` | Preset Options |
| [`server_version_num`](/parameters/server-version-num/) | `140024` | `150019` | Preset Options |
| [`shared_buffers`](/parameters/shared-buffers/) | `1024 8kB` (8 MiB (1024 × 8kB)) | `16384 8kB` (128 MiB (16384 × 8kB)) | Resource Usage / Memory |
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## Removed parameters {#removed}

| Parameter | Last type | Context | Last boot default | Category |
| --- | --- | --- | --- | --- |
| [`stats_temp_directory`](/parameters/stats-temp-directory/) | `string` | `sighup` | `pg_stat_tmp` | Statistics / Query and Index Statistics Collector |
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## Method {#method}

The three lists compare the pinned PG14 and PG15 `pg_settings` snapshots directly. A default change is a change in the `boot_val` plus `unit` pair; `setting` is excluded so an `initdb`-generated value is not mistaken for the compiled boot default.

- [Machine-readable diff data](/data/diffs.json)
- [Complete GUC JSONL](/data/guc.jsonl)