12 Change of Configuration Parameters
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In PostgreSQL 10 the following parameters have been changed.
3.10.1 Added parameters
The following parameters have been added.
| Parameter name | Description (context) | Default |
|---|---|---|
| enable_gathermerge | Enable execution plan Gather Merge (user) | on |
| max_parallel_workers | Maximum number of parallel worker process (user) | 8 |
| max_sync_workers_per_subscription | Maximum number of synchronous workers for SUBSCRIPTION (sighup) | 2 |
| wal_consistency_checking | Check the consistency of WAL on the standby instance (superuser) | - |
| max_logical_replication_workers | Maximum number of Logical Replication worker process (postmaster) | 4 |
| max_pred_locks_per_relation | Maximum number of pages that can be Predicate- Lock before locking the entire relation (sighup) | -2 |
| max_pred_locks_per_page | Maximum number of records that can be Predicate-Lock before locking the entire page (sighup) | 2 |
| min_parallel_table_scan_size | Minimum table size at which Parallel table scan are considered (user) | 8MB |
| min_parallel_index_scan_size | Minimum table size at which Parallel index scan are considered (user) | 512kB |
Parameter max_parallel_workers
Specifies the maximum number of parallel query worker processes that can run concurrently in the instances. The default value is 8. In the old version, the max_worker_processes parameter was the upper limit. If this value is set to 0, the parallel query is invalidated.
Parameter max_logical_replication_workers
Specifies the maximum value of the Logical Replication Worker processes to be started for each SUBSCRIPTION. Even if the value of this parameter is less than the required value, CREATE
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SUBSCRIPTION statement will not fail. The following logs are periodically output when replication starts.
Parameter wal_consistency_checking
This parameter is used for bug checking of the WAL re-execution program in the replication environment. For the parameter, specify the object type to be checked with a comma (,) delimiter. The following values are available: all, hash, heap, heap 2, btree, gin, gist, sequence, spgist, brin, generic.
Parameter max_pred_locks_per_page
Specifies the maximum number of tuple locks to transition to page lock.
Parameter max_pred_locks_per_relation
Specifies the maximum number of page locks to transition to relation lock.
3.10.2 Changed parameters
The setting range and options were changed for the following configuration parameters.
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| ssl | changed to sighup |
|---|---|
| ssl_ca_file | The value of the context column has been changed to sighup |
| ssl_cert_file | The value of the context column has been changed to sighup |
| ssl_ciphers | The value of the context column has been changed to sighup |
| ssl_crl_file | The value of the context column has been changed to sighup |
| ssl_ecdh_curve | The value of the context column has been changed to sighup |
| ssl_key_file | The value of the context column has been changed to sighup |
| ssl_prefer_server_ciphers | The value of the context column has been changed to sighup |
| bgwriter_lru_maxpages | The value of max_val column was changed to INT_MAX / 2 |
| archive_timeout | The value of the short_desc column has changed |
| server_version_num | The value of max_val / min_val column was changed to 100000 |
| password_encryption | The value of the vartype was changed to enum. “md5” or “scram-sha- 256” can specified. “on” is a alias for “md5” |
| max_wal_size | The value of the unit column has been changed to 1MB |
| min_wal_size | The value of the unit column has been changed to 1MB |
Parameter name Changes
3.10.3 Parameters with default values changed
The default values of the following configuration parameters have been changed.
| Parameter name | PostgreSQL 9.6 | PostgreSQL 10 |
|---|---|---|
| hot_standby | off | on |
| log_line_prefix | '' | %m [%p] |
| max_parallel_workers_per_gather | 0 | 2 |
| max_replication_slots | 0 | 10 |
| max_wal_senders | 0 | 10 |
| password_encryption | on | md5 |
| server_version | 9.6.3 | 10beta1 |
| server_version_num | 90603 | 100000 |
| wal_level | minimal | replica |
| log_directory | pg_log | log |
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Parameter log_line_prefix
The parameter default value has been changed.
3.10.4 Deprecated parameters
The following parameters are deprecated.
| Parameter name | Alternative value |
|---|---|
| min_parallel_relation_sizesql_inheritance | Changed to min_parallel_table_scan_size None (same as ‘on’) |
3.10.5 New function of authentication method
The following changes were made to the pg_hba.conf file.
Specify the RADIUS server
The specification of the RADIUS server necessary for RADIUS authentication changed from “radiusserver” to “radiusservers”. Multiple servers separated by commas can be specified.
Added SCRAM authentication
Scram-sha-256 can be specified for the authentication method in pg_hba.conf. This is an implementation of SCRAM-SHA-256 as specified in RFC 5802 and 7677. Scram-sha-256 can also be specified for configuration parameter password_encryption.
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3.10.6 Default value of authentication setting
The replication related default value contained in the pg_hba.conf file has been changed. By default, the local connection is set to the “trust” setting.
3.10.7 Other parameter change
The parameter recovery_target_lsn related to “Point In Time Recovery” has been added to the recovery.conf file. For this parameter, specify the recovery complete LSN.