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In PostgreSQL 10 the following parameters have been changed. #### 3.10.1 Added parameters {#pg10-3-10-1-added-parameters} The following parameters have been added. **Table 26.** Added parameters | 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 {#pg10-p81-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 {#pg10-p81-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, CREATEPDF page 82
SUBSCRIPTION statement will not fail. The following logs are periodically output when replication starts. **Example 91.** Lack max\_logical\_replication\_workers parameters ```text WARNING: out of logical replication worker slots HINT: You might need to increase max_logical_replication_workers. ``` ##### Parameter wal_consistency_checking {#pg10-p82-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 {#pg10-p82-parameter-max-pred-locks-per-page} Specifies the maximum number of tuple locks to transition to page lock. ##### Parameter max_pred_locks_per_relation {#pg10-p82-parameter-max-pred-locks-per-relation} Specifies the maximum number of page locks to transition to relation lock. #### 3.10.2 Changed parameters {#pg10-3-10-2-changed-parameters} The setting range and options were changed for the following configuration parameters.PDF page 83
**Table 27.** Changed configuration parameters \(from pg\_settings catalog\) | 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 {#pg10-3-10-3-parameters-with-default-values-changed} The default values of the following configuration parameters have been changed. **Table 28.** Parameters with default values 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 |PDF page 84
##### Parameter log_line_prefix {#pg10-p84-parameter-log-line-prefix} The parameter default value has been changed. **Example 92.** Parameter log\_line\_prefix default ```text postgres=# SHOW log_line_prefix ; log_line_prefix ----------------- %m [%p] (1 row) $ tail -1 data/log/postgresql-2017-05-20_093448.log 2017-05-20 09:34:48.617 JST [12187] LOG: autovacuum launcher started ``` #### 3.10.4 Deprecated parameters {#pg10-3-10-4-deprecated-parameters} The following parameters are deprecated. **Table 29.** Deprecated parameters | 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 {#pg10-3-10-5-new-function-of-authentication-method} The following changes were made to the pg_hba.conf file. ##### Specify the RADIUS server {#pg10-p84-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 {#pg10-p84-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.PDF page 85
#### 3.10.6 Default value of authentication setting {#pg10-3-10-6-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. **Example 93.** Default setting of pg\_hba\.conf file ```bash # Allow replication connections from localhost, by a user with the # replication privilege. local replication all trust host replication all 127.0.0.1/32 trust host replication all ::1/128 trust ``` #### 3.10.7 Other parameter change {#pg10-3-10-7-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.