5 Configuration Parameters
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In PostgreSQL 18, the following parameters have been changed.
3.3.1 Added parameters
The following parameters have been added. [0dcaea5, db6a4a9, c758119, a8ccf4e, 306dc52, 052026c, bb8dff9, 45188c2, 3d1ef3a, fc069a3, ac0e331, b3f0be7, 6c349d8, 6d376c3, 0284401, 4f7f7b0, 10f6646, 0164a0f, 247ce06, 55b454d, 62d712e, 9fbd53d, f78ca6f, 73bdcfa, 05dedf4]
| Parameter name | Description (context) | Default value |
|---|---|---|
| autovacuum_worker_slots | Maximum number of autovacuum max workers settings__ (postmaster) | 16 |
| autovacuum_vacuum_max_threshold | Maximum number of tuples required to trigger VACUUM on a table (sighup) | 100000000 |
| enable_distinct_reordering | Whether to use column reordering optimization specified in the DISTINCT clause (user) | on |
| enable_self_join_elimination | Enable self-join optimization feature (user) | on |
| extension_control_path | Extended control file path (superuser) | $system |
| file_copy_method | Specify how files are copied (user) | copy |
| idle_replication_slot_timeout | Number of idle seconds to disable replication slots (sighup) | 0 |
| io_max_combine_limit | Maximum value for io_combine_limit (postmaster) | 16 |
| io_max_concurrency | Maximum number of simultaneous I/Os a single process can perform (postmaster) | 64 |
| io_method | Asynchronous I/O execution method (postmaster) | worker |
| io_workers | Number of IO worker processes （sighup） | 3 |
| log_lock_failures | （sighup） Log output when lock fails (superuser) | off |
| max_active_replication_origins | Maximum number of replication origins | 10 |
| Maximum number of replication origins | 10 | |
| md5_password_warnings | Output warning when generating MD5 passwords (user) | on |
| num_os_semaphores | Number of semaphores required to run the server (internal) | 計算値 |
| oauth_validator_libraries | Library used to validate OAuth connection tokens (sighup) | '' |
| ssl_groups | Curve name used for EDCH key exchange | X25519:prime2 |
| (sighup) | 56v1 | |
| ssl_tls13_ciphers | List of cipher suites that can be used for connections with TLS version 1.3 (sighup) | '' |
| track_cost_delay_timing | Cost-based VACUUM delay tracking (superuser) | off |
| vacuum_max_eager_freeze_failure_rate | Percentage of pages where VACUUM disables EAGER scans (user) | 0.03 |
| vacuum_truncate | Enables vacuum to truncate empty pages at the end of the table (user) | on |
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Maximum number of autovacuum worker processes
The autovacuum_max_workers parameter can now be changed dynamically by executing the pg_reload_conf function. The parameter autovacuum_worker_slots (default 16) has been added to indicate the upper limit for dynamic changes. autovacuum_max_workers parameter setting can be larger than autovacuum_worker_slots, but the autovacuum_max_workers parameter setting will not be changed. but it will not launch more worker processes than autovacuum_worker_slots. [c758119, 6d01541]
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3.3.2 Modified Parameters
The following parameters have been changed in terms of setting range and choices. [d0c2860, e48b19c, 7c3fb50, c758119, d4c3a6b, 9219093, 3516ea7]
| Parameter name | Change |
|---|---|
| autovacuum_max_workers | Changed to dynamically updatable (context=sighup) |
| log_rotation_size | Upper limit changed to 2,147,483,647 |
| log_connections | Changed to string type from boolean type |
| log_line_prefix | Escape %L indicating local IP address can be used |
| max_files_per_process | Exclude the number of files inherited by the backend |
| ssl_groups | Changed name from ssl_ecdh_curve |
Parameter log_connections is changed
The parameter log_connections has been changed from a boolean type to a text type, allowing multiple settings of log output to be comma-separated. [9219093, 18cd15e]
| Setting value | Output contents |
|---|---|
| '' | No logging (default value) |
| receipt | Log when a connection is received |
| authentication | Log the ID that identifies the user |
| authorization | Log the completion of authentication |
| setup_durations | Log the time between when the connection is made and when the first query is ready to be executed |
| all | Same as receipt,authentication,authorization,setup_durations |
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3.3.3 Parameters with default values changed
The following parameters have changed default values. [98f320e, 9219093, ff79b5b, cc6be07, daa02c6]
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| Parameter name | PostgreSQL 17 | PostgreSQL 18 | Note |
|---|---|---|---|
| server_version | 17.5 | 18.0 | |
| server_version_numdata_checksums | 170005 | 180000 | |
| off | on | ||
| log_connections | off | '' | |
| effective_io_concurrency | 1 | 16 | |
| maintenance_io_concurrencyssl_groups | 10 | 16 | |
| prime256v1 | X25519:prime256v1 Parameter | X25519:prime256v1 Parameter name change |