PostgreSQL 16 → 17 GUC diff
Core configuration parameters added, removed, or changed in boot default between PostgreSQL 16 and 17.
Note
Fact. The measured inventory changes from 364 to 380 settings: 19 added, 3 boot-default changes, and 3 removed.
Added parameters
| Parameter | Type | Context | Boot default | Category |
|---|---|---|---|---|
allow_alter_system |
bool |
sighup |
on |
Version and Platform Compatibility / Other Platforms and Clients |
commit_timestamp_buffers |
integer |
postmaster |
0 8kB (0 B (0 × 8kB)) |
Resource Usage / Memory |
enable_group_by_reordering |
bool |
user |
on |
Query Tuning / Planner Method Configuration |
event_triggers |
bool |
superuser |
on |
Client Connection Defaults / Statement Behavior |
huge_pages_status |
enum |
internal |
unknown |
Preset Options |
io_combine_limit |
integer |
user |
16 8kB (128 KiB (16 × 8kB)) |
Resource Usage / Asynchronous Behavior |
max_notify_queue_pages |
integer |
postmaster |
1048576 |
Resource Usage / Disk |
multixact_member_buffers |
integer |
postmaster |
32 8kB (256 KiB (32 × 8kB)) |
Resource Usage / Memory |
multixact_offset_buffers |
integer |
postmaster |
16 8kB (128 KiB (16 × 8kB)) |
Resource Usage / Memory |
notify_buffers |
integer |
postmaster |
16 8kB (128 KiB (16 × 8kB)) |
Resource Usage / Memory |
serializable_buffers |
integer |
postmaster |
32 8kB (256 KiB (32 × 8kB)) |
Resource Usage / Memory |
subtransaction_buffers |
integer |
postmaster |
0 8kB (0 B (0 × 8kB)) |
Resource Usage / Memory |
summarize_wal |
bool |
sighup |
off |
Write-Ahead Log / Summarization |
sync_replication_slots |
bool |
sighup |
off |
Replication / Standby Servers |
synchronized_standby_slots |
string |
sighup |
"" (empty string) |
Replication / Primary Server |
trace_connection_negotiation |
bool |
postmaster |
off |
Developer Options |
transaction_buffers |
integer |
postmaster |
0 8kB (0 B (0 × 8kB)) |
Resource Usage / Memory |
transaction_timeout |
integer |
user |
0 ms |
Client Connection Defaults / Statement Behavior |
wal_summary_keep_time |
integer |
sighup |
14400 min (10 d) |
Write-Ahead Log / Summarization |
Boot-default changes
| Parameter | PG16 | PG17 | Category |
|---|---|---|---|
server_version |
16.15 (Debian 16.15-1.pgdg13+2) |
17.11 (Debian 17.11-1.pgdg13+2) |
Preset Options |
server_version_num |
160015 |
170011 |
Preset Options |
vacuum_buffer_usage_limit |
256 kB (256 KiB) |
2048 kB (2 MiB) |
Resource Usage / Memory |
Removed parameters
| Parameter | Last type | Context | Last boot default | Category |
|---|---|---|---|---|
db_user_namespace |
bool |
sighup |
off |
Connections and Authentication / Authentication |
old_snapshot_threshold |
integer |
postmaster |
-1 min |
Resource Usage / Asynchronous Behavior |
trace_recovery_messages |
enum |
sighup |
log |
Developer Options |
Method
The three lists compare the pinned PG16 and PG17 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.