PolarDB for PostgreSQL parameter default value changes-PolarDB(PolarDB)-阿里云帮助中心

Starting with minor engine versions V1.1.28 (PostgreSQL 11) and V14.5.1.1 (PostgreSQL 14), changed default values for several parameters.

Check your engine version

Note Run one of these statements to check your cluster's minor engine version:

The following parameters have new defaults:

Parameter	Previous Default	New Default	Description
synchronous_commit	on	off	Controls whether transactions wait for WAL records to reach disk before the commit returns. Valid values: off (default): The transaction commits without waiting for WAL records to reach disk. Note A commit may not persist to disk immediately. The maximum delay is three times wal_writer_delay (default: 10 ms). This improves commit performance. on: The transaction waits for WAL records to reach disk before the commit returns. Note If your application requires immediate durability after commit, set this parameter to on in the console. Note To view the current setting: `show synchronous_commit;`
wal_level	logical	replica	Controls how much information is written to the WAL. Valid values: replica (default): Excludes logical decoding information from WAL, reducing write volume and improving performance. logical: Includes logical replication information in WAL, increasing write volume. Warning Changing this parameter restarts the database. Proceed with caution. Note To view the current setting: `show wal_level;`
log_statement	all	ddl	Sets the audit log level. The default ddl audits only DDL statements, reducing log volume and improving performance. Note To audit all SQL statements, enable SQL Explorer in the console. To view the current setting: `show log_statement;`

Note All cluster parameter defaults are documented in Default Values for Cluster Parameters.