Supported database flags

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This page lists the database flags that AlloyDB supports.

You use database flags for many operations, including adjusting PostgreSQL parameters, adjusting options, and configuring and tuning instances.

In some cases, setting one flag may require that you set another flag to fully enable the desired functionality.

When you set, remove, or modify a flag for an instance, the instance might be restarted. The flag value is then persisted for the instance until you remove it.

Flags not mentioned below are not supported.

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AlloyDB Flag Type
Acceptable Values and Notes		 Restart
Required?
alloydb.enable_auto_explain boolean
on | off		 Yes
alloydb.enable_pg_bigm boolean
on | off		 Yes
alloydb.enable_pg_cron boolean
on | off		 Yes
alloydb.enable_pg_hint_plan boolean
on | off		 Yes
alloydb.enable_pgaudit boolean
on | off		 Yes
alloydb.enable_pglogical boolean
on | off		 Yes
alloydb.logical_decoding boolean
on | off		 Yes
alloydb.pg_shadow_select_role string No
auto_explain.log_analyze boolean
on | off		 No
auto_explain.log_buffers boolean
on | off		 No
auto_explain.log_format enumeration
text | xml | json | yaml		 No
auto_explain.log_level enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | debug | info | notice | warning | log		 No
auto_explain.log_min_duration integer
-1 ... 2147483647		 No
auto_explain.log_nested_statements boolean
on | off		 No
auto_explain.log_settings boolean
on | off		 No
auto_explain.log_timing boolean
on | off		 No
auto_explain.log_triggers boolean
on | off		 No
auto_explain.log_verbose boolean
on | off		 No
auto_explain.log_wal boolean
on | off		 No
auto_explain.sample_rate float
0 ... 1		 No
autovacuum boolean
on | off		 No
autovacuum_analyze_scale_factor float
0 ... 100		 No
autovacuum_analyze_threshold integer
0 ... 2147483647		 No
autovacuum_freeze_max_age integer
100000 ... 2000000000		 Yes
autovacuum_max_workers integer
1 ... 262143		 Yes
autovacuum_multixact_freeze_max_age integer
10000 ... 2000000000		 Yes
autovacuum_naptime integer
1 ... 2147483		 No
autovacuum_vacuum_cost_delay integer
-1 ... 100		 No
autovacuum_vacuum_cost_limit integer
-1 ... 10000		 No
autovacuum_vacuum_scale_factor float
0 ... 100		 No
autovacuum_vacuum_threshold integer
0 ... 2147483647		 No
autovacuum_work_mem integer
-1 ... 2147483647
Unit is kB.		 No
checkpoint_completion_target float
0 ... 1		 No
checkpoint_timeout integer
30 ... 86400
Unit is s.		 No
checkpoint_warning integer
0 ... 2147483647
Unit is s.		 No
commit_delay integer
0 ... 100000		 No
commit_siblings integer
0 ... 1000		 No
constraint_exclusion enumeration
partition | on | off		 No
cpu_index_tuple_cost float
0 ... 3.4028235e+38		 No
cpu_operator_cost float
0 ... 3.4028235e+38		 No
cpu_tuple_cost float
0 ... 3.4028235e+38		 No
cron.database_name string Yes
cron.log_min_messages enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | debug | info | notice | warning | error | log | fatal | panic		 No
cron.log_run boolean
on | off		 Yes
cron.log_statement boolean
on | off		 Yes
cron.max_running_jobs integer
0		 Yes
cursor_tuple_fraction float
0 ... 1		 No
deadlock_timeout integer
1 ... 2147483647
Unit is ms.		 No
default_statistics_target integer
1 ... 10000		 No
default_tablespace string No
default_transaction_deferrable boolean
on | off		 No
default_transaction_isolation enumeration
serializable | 'repeatable read' | 'read committed' | 'read uncommitted'
Single quotes are required around enumeration strings that contain spaces.		 No
effective_cache_size integer
1 ... 2147483647
Unit is blocks.		 No
enable_bitmapscan boolean
on | off		 No
enable_hashagg boolean
on | off		 No
enable_hashjoin boolean
on | off		 No
enable_indexonlyscan boolean
on | off		 No
enable_indexscan boolean
on | off		 No
enable_material boolean
on | off		 No
enable_mergejoin boolean
on | off		 No
enable_nestloop boolean
on | off		 No
enable_seqscan boolean
on | off		 No
enable_sort boolean
on | off		 No
enable_tidscan boolean
on | off		 No
force_parallel_mode enumeration
off | on | regress		 No
from_collapse_limit integer
1 ... 2147483647		 No
geqo boolean
on | off		 No
geqo_effort integer
1 ... 10		 No
geqo_generations integer
0 ... 2147483647		 No
geqo_pool_size integer
0 ... 2147483647		 No
geqo_seed float
0 ... 1		 No
geqo_selection_bias float
1.5 ... 2		 No
geqo_threshold integer
2 ... 2147483647		 No
gin_fuzzy_search_limit integer
0 ... 2147483647		 No
gin_pending_list_limit integer
64 ... 2147483647
Unit is kB.		 No
google_columnar_engine.column_set_stat_statements_max_memory_size integer
1048576 ... 2147483647		 Yes
google_columnar_engine.memory_size_in_mb integer
128 ... 2147483647		 Yes
google_columnar_engine.enable_columnar_recommendation boolean
on | off		 No
google_columnar_engine.enable_columnar_scan boolean
on | off		 No
google_columnar_engine.enabled boolean
on | off		 Yes
google_columnar_engine.estimate_relation_size_sampling_percentage float
0.0 ... 100.0		 No
google_columnar_engine.hypothetical_config_max_memory_size integer
1048576 ... 2147483647		 Yes
google_columnar_engine.maintenance_cpu_percentage integer
0 ... 100		 No
google_columnar_engine.max_num_pending_whatif_analysis integer
1 ... 2147483647		 Yes
google_columnar_engine.max_parallel_workers_per_job integer
0 ... 262143		 No
google_columnar_engine.max_sampled_query_length integer
1 ... 2147483647		 Yes
google_columnar_engine.query_sampling_percentage float
0 ... 100		 No
google_columnar_engine.refresh_threshold_percentage integer
-1 ... 100		 No
google_columnar_engine.refresh_threshold_scan_count integer
0 ... 2147483647		 No
google_columnar_engine.relations string No
google_columnar_engine.scan_mode integer
0 ... 2		 No
hot_standby_feedback boolean
on | off		 No
idle_in_transaction_session_timeout integer
0 ... 2147483647
Unit is ms.		 No
join_collapse_limit integer
1 ... 2147483647		 No
lock_timeout integer
0 ... 2147483647
Unit is ms.		 No
log_autovacuum_min_duration integer
-1 ... 2147483647		 No
log_checkpoints boolean
on | off		 No
log_connections boolean
on | off		 No
log_disconnections boolean
on | off		 No
log_duration boolean
on | off		 No
log_error_verbosity enumeration
terse | default | verbose		 No
log_executor_stats boolean
on | off		 No
log_hostname boolean
on | off		 No
log_lock_waits boolean
on | off		 No
log_min_duration_statement integer
-1 ... 2147483647
Unit is ms.		 No
log_min_error_statement enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | info | notice | warning | error | log | fatal | panic		 No
log_min_messages enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | info | notice | warning | error | log | fatal | panic		 No
log_parser_stats boolean
on | off		 No
log_planner_stats boolean
on | off		 No
log_replication_commands boolean
on | off		 No
log_statement enumeration
none | ddl | mod | all		 No
log_statement_stats boolean
on | off		 No
log_temp_files integer
-1 ... 2147483647
Unit is kB.		 No
maintenance_work_mem integer
1024 ... 2147483647
Unit is kB.		 No
max_connections integer
1000 ... 240000
This flag's value on a read pool instance must be greater than or equal to the value on the primary instance.
Also, the minimum provides at most 970 non-superuser connections, as the superuser_reserved_connections flag reserves 30 connections.		 Yes
max_locks_per_transaction integer
10 ... 2147483647
This flag's value on a read pool instance must be greater than or equal to the value on the primary instance.		 Yes
max_logical_replication_workers integer
4 ... 8192
Maxiumum value is dependent on instance memory and limited to max_worker_processes.		 Yes
max_parallel_workers integer
0 ... 1024
Maximum value is dependent on instance memory.		 No
max_parallel_workers_per_gather integer
0 ... 1024
Maximum value is dependent on instance memory.		 No
max_pred_locks_per_page integer
0 ... 2147483647		 Yes
max_pred_locks_per_relation integer
-2147483648 ... 2147483647		 Yes
max_pred_locks_per_transaction integer
10 ... 1048576		 Yes
max_prepared_transactions integer
0 ... 262143
This flag's value on a read pool instance must be greater than or equal to the value on the primary instance.		 Yes
max_replication_slots integer
10 ... 8192
Maximum value is dependent on instance memory.		 Yes
max_standby_archive_delay integer
-1 ... 2147483647
Unit is ms.		 No
max_standby_streaming_delay integer
-1 ... 2147483647
Unit is ms.		 No
max_sync_workers_per_subscription integer
2 ... 64
Limited by max_logical_replication_workers.		 No
max_wal_senders integer
10 ... 8192
This flag's value on a read pool instance must be greater than or equal to the value on the primary instance. Also, maximum value is dependent on instance memory.		 Yes
max_wal_size integer
32 ... 2147483647
Unit is MB. Must be at least twice wal_segment_size.		 No
max_worker_processes integer
8 ... 4096
This flag's value on a read pool instance must be greater than or equal to the value on the primary instance. Also, maximum value is dependent on instance memory.		 Yes
min_parallel_relation_size integer
0 ... 715827882
Unit is 8kB.		 No
min_wal_size integer
32 ... 2147483647
Unit is MB. Must be at least twice wal_segment_size.		 No
old_snapshot_threshold integer
-1 ... 86400
Unit is min.		 Yes
parallel_setup_cost float
0 ... 3.4028235e+38		 No
parallel_tuple_cost float
0 ... 3.4028235e+38		 No
password_encryption enumeration
md5 | scram-sha-256		 No
pg_bigm.enable_recheck boolean
on | off		 No
pg_bigm.gin_key_limit integer
0 ... 2147483647		 No
pg_bigm.similarity_limit float
0 ... 1		 No
pg_hint_plan.debug_print enumeration
off | on | detailed | verbose | 0 | 1 | 2 | 3 | no | yes | false | true		 No
pg_hint_plan.enable_hint boolean
on | off		 No
pg_hint_plan.enable_hint_table boolean
on | off		 No
pg_hint_plan.message_level enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | debug | info | notice | warning | error | log		 No
pg_hint_plan.parse_messages enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | debug | info | notice | warning | error | log		 No
pg_stat_statements.max integer
100 ... 2147483647		 Yes
pg_stat_statements.save boolean
on | off		 No
pg_stat_statements.track enumeration
none | top | all		 No
pg_stat_statements.track_utility boolean
on | off		 No
pgaudit.log enumeration
read | write | function | role | ddl | misc | misc_set | all | none | -read | -write | -function | -role | -ddl | -misc | -misc_set | -all | -none		 No
pgaudit.log_catalog boolean
on | off		 No
pgaudit.log_client boolean
on | off		 No
pgaudit.log_level enumeration
debug | debug5 | debug4 | debug3 | debug2 | debug1 | info | notice | warning | log		 No
pgaudit.log_parameter boolean
on | off		 No
pgaudit.log_relation boolean
on | off		 No
pgaudit.log_statement_once boolean
on | off		 No
pgaudit.role string No
pglogical.batch_inserts boolean
on | off		 Yes
pglogical.conflict_log_level enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | info | notice | warning | error | log | fatal | panic		 No
pglogical.conflict_resolution enumeration
error | apply_remote | keep_local | last_update_wins | first_update_wins		 No
pglogical.extra_connection_options string No
pglogical.synchronous_commit boolean
on | off		 Yes
pglogical.use_spi boolean
on | off		 Yes
random_page_cost float
0 ... 3.4028235e+38		 No
replacement_sort_tuples integer
0 ... 2147483647		 No
shared_buffers integer
16 ... 1073741823
Unit is blocks.		 Yes
ssl_max_protocol_version enumeration
TLSv1 | TLSv1.1 | TLSv1.2 | TLSv1.3		 No
ssl_min_protocol_version enumeration
TLSv1 | TLSv1.1 | TLSv1.2 | TLSv1.3		 No
standard_conforming_strings boolean
on | off		 No
statement_timeout integer
0 ... 2147483647
Unit is ms.		 No
synchronize_seqscans boolean
on | off		 No
tcp_keepalives_count integer
0 ... 2147483647		 No
tcp_keepalives_idle integer
0 ... 2147483647		 No
tcp_keepalives_interval integer
0 ... 2147483647		 No
temp_buffers integer
100 ... 1073741823
Unit is 8kB.		 No
temp_file_limit integer
1048576 ... 2147483647
Unit is kB.		 No
trace_notify boolean
on | off		 No
trace_recovery_messages enumeration
debug5 | debug4 | debug3 | debug2 | debug1 | log | notice | warning | error		 No
trace_sort boolean
on | off		 No
track_activities boolean
on | off		 No
track_activity_query_size integer
100 ... 102400		 Yes
track_commit_timestamp boolean
on | off		 Yes
track_counts boolean
on | off		 No
track_functions enumeration
none | pl | all		 No
track_io_timing boolean
on | off		 No
vacuum_cost_delay integer
0 ... 100
Unit is ms.		 No
vacuum_cost_limit integer
1 ... 10000		 No
vacuum_freeze_min_age integer
0 ... 1000000000		 No
vacuum_freeze_table_age integer
0 ... 2000000000		 No
vacuum_multixact_freeze_min_age integer
0 ... 1000000000		 No
vacuum_multixact_freeze_table_age integer
0 ... 2000000000		 No
wal_buffers integer
-1 ... 262143
Unit is blocks.		 Yes
work_mem integer
64 ... 2147483647
Unit is kB.		 No