本文介绍了数据库集群参数默认值的详细信息。
参数说明
PolarDB PostgreSQL版（兼容Oracle）参数默认值的设置，综合了性能、可用性以及可靠性方面的考虑，与社区版本默认值不一定相同。特别是以下参数，PolarDB根据最优性能原则进行了默认设定，您可以根据自己的需求在控制台自行修改。
参数 | 默认值 | 说明 |
polar_comp_stmt_level_tx | off | 该参数用于控制异常是否回滚未提交的数据库更新。取值如下：
说明
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log_statement | ddl | 该参数用于设置审计日志的级别。默认为ddl，表示只有DDL对应的SQL才会进行审计，更少的日志打印可以提升数据库性能。 说明
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常见参数默认值设置情况
参数 | 默认值 |
authentication_timeout | 60 |
autovacuum | on |
autovacuum_analyze_scale_factor | 0.05 |
autovacuum_analyze_threshold | 50 |
autovacuum_freeze_max_age | 1200000000 |
autovacuum_max_workers | 5 |
autovacuum_multixact_freeze_max_age | 1400000000 |
autovacuum_naptime | 30 |
autovacuum_vacuum_cost_delay | 0 |
autovacuum_vacuum_cost_limit | 10000 |
autovacuum_vacuum_scale_factor | 0.02 |
autovacuum_vacuum_threshold | 50 |
backend_flush_after | 0 |
bgwriter_delay | 10 |
checkpoint_timeout | 30 |
constraint_exclusion | partition |
cpu_index_tuple_cost | 0.005 |
cpu_operator_cost | 0.0025 |
cpu_tuple_cost | 0.01 |
datestyle | 'ISO,YMD' |
deadlock_timeout | 1000 |
default_with_oids |
|
dynamic_shared_memory_type | posix |
enable_partition_pruning | on |
extra_float_digits | 0 |
fsync | on |
full_page_writes | off |
gin_pending_list_limit | 4096 |
hot_standby | on |
hot_standby_feedback | on |
huge_pages | on |
idle_in_transaction_session_timeout | 3600000 |
jit | off |
lock_timeout | 0 |
logging_collector | on |
log_connections | off |
log_disconnections | off |
log_error_verbosity | default |
log_min_duration_statement | 5000 |
log_statement | ddl |
max_files_per_process | 1000 |
max_locks_per_transaction | 64 |
max_prepared_transactions | 800 |
max_replication_slots | 64 |
max_worker_processes | 256 |
polar_comp_stmt_level_tx | off |
seq_page_cost | 1 |
ssl | off |
statement_timeout | 0 |
synchronous_commit | on |
temp_file_limit | 524288000 |
timezone | 'UTC' |
wal_buffers | 16 MB |
wal_level | logical |
wal_writer_delay | 10 |