Summary of configuration parameters v16
This summary table list all EDB Postgres Advanced Server configuration parameters along with a number of key attributes of the parameters.
These attributes are described by the following columns of the summary table:
Parameter — Configuration parameter name and a brief description of the configuration parameter. Parameters for use only with EDB Postgres Advanced Server (EPAS) are denoted by (EPAS only).
Scope — Scope of effect of the configuration parameter setting:
Cluster
— Setting affects the entire database cluster, that is, all databases managed by the database server instance.Database
— Setting can vary by database and is established when the database is created. Applies to a small number of parameters related to locale settings.Session
— Setting can vary down to the granularity of individual sessions.
In other words, different settings can be made for the following entities in which the latter settings in this list override prior ones:
- The entire database cluster
- Specific databases in the database cluster
- Specific roles
- Specific roles when connected to specific databases
- A specific session
In effect — When a changed parameter setting takes effect:
Preset
— Established when the EDB Postgres Advanced Server product is built or a particular database is created. This is a read-only parameter and can't be changed.Restart
— You must restart the database server.Reload
— You must reload configuration file or restart the database server.Immediately
— Immediately effective in a session if thePGOPTIONS
environment variable or theSET
command is used to change the setting in the current session. Effective in new sessions ifALTER DATABASE
,ALTER ROLE
, orALTER ROLE IN DATABASE
commands are used to change the setting.
Used by — Type of operating system account or database role that must be used to put the parameter setting into effect.
EPAS account
— The EDB Postgres Advanced Server service account (enterprisedb
for an installation compatible with Oracle databases,postgres
for a PostgreSQL compatible mode installation).Superuser
— Database role with superuser privileges.User
— Any database role with permissions on the affected database object, that is, the database or role to alter with theALTER
command.n/a
— No user can change the parameter setting.
Note
Some parameters can never be altered. These are designated as Note: For internal use only in the description.
Parameter | Scope | In effect | Used by |
---|---|---|---|
allow_system_table_mods — Allows modifications of the structure of system tables. | Cluster | Restart | EPAS account |
application_name — Sets the application name to be reported in statistics and logs. | Session | Immediately | User |
archive_command — Sets the shell command called to archive a WAL file. | Cluster | Reload | EPAS account |
archive_mode — Allows archiving of WAL files using archive_command . | Cluster | Restart | EPAS account |
archive_timeout — Forces a switch to the next xlog file if a new file has not been started within N seconds. | Cluster | Reload | EPAS account |
array_nulls — Enables input of NULL elements in arrays. | Session | Immediately | User |
authentication_timeout — Sets the maximum allowed time to complete client authentication. | Cluster | Reload | EPAS account |
autovacuum — Starts the autovacuum subprocess. | Cluster | Reload | EPAS account |
autovacuum_analyze_scale_factor — Number of tuple inserts, updates, or deletes prior to analyze as a fraction of reltuples . | Cluster | Reload | EPAS account |
autovacuum_analyze_threshold — Minimum number of tuple inserts, updates, or deletes prior to analyze. | Cluster | Reload | EPAS account |
autovacuum_freeze_max_age — Age at which to autovacuum a table to prevent transaction ID wraparound. | Cluster | Restart | EPAS account |
autovacuum_max_workers — Sets the maximum number of simultaneously running autovacuum worker processes. | Cluster | Restart | EPAS account |
autovacuum_multixact_freeze_max_age — Multixact age at which to autovacuum a table to prevent multixact wraparound. | Cluster | Restart | EPAS account |
autovacuum_naptime — Time to sleep between autovacuum runs. | Cluster | Reload | EPAS account |
autovacuum_vacuum_cost_delay — Vacuum cost delay in milliseconds, for autovacuum. | Cluster | Reload | EPAS account |
autovacuum_vacuum_cost_limit — Vacuum cost amount available before napping, for autovacuum. | Cluster | Reload | EPAS account |
autovacuum_vacuum_scale_factor — Number of tuple updates or deletes prior to vacuum as a fraction of reltuples . | Cluster | Reload | EPAS account |
autovacuum_vacuum_threshold — Minimum number of tuple updates or deletes prior to vacuum. | Cluster | Reload | EPAS account |
autovacuum_work_mem — Sets the maximum memory to be used by each autovacuum worker process. | Cluster | Reload | EPAS account |
backslash_quote — Sets whether "\'" is allowed in string literals. | Session | Immediately | User |
bgwriter_delay — Background writer sleep time between rounds. | Cluster | Reload | EPAS account |
bgwriter_lru_maxpages — Background writer maximum number of LRU pages to flush per round. | Cluster | Reload | EPAS account |
bgwriter_lru_multiplier — Multiple of the average buffer usage to free per round. | Cluster | Reload | EPAS account |
block_size — Shows the size of a disk block. | Cluster | Preset | n/a |
bonjour — Enables advertising the server via Bonjour. | Cluster | Restart | EPAS account |
bonjour_name — Sets the Bonjour service name. | Cluster | Restart | EPAS account |
bytea_output — Sets the output format for bytea . | Session | Immediately | User |
check_function_bodies — Checks function bodies during CREATE FUNCTION . | Session | Immediately | User |
checkpoint_completion_target — Time spent flushing dirty buffers during checkpoint, as fraction of checkpoint interval. | Cluster | Reload | EPAS account |
checkpoint_segments (Deprecated) — Specifies a value for the parameter prevents the server from starting. | - | ||
checkpoint_timeout — Sets the maximum time between automatic WAL checkpoints. | Cluster | Reload | EPAS account |
checkpoint_warning — Enables warnings if checkpoint segments are filled more frequently than this. | Cluster | Reload | EPAS account |
client_encoding — Sets the client's character set encoding. | Session | Immediately | User |
client_min_messages — Sets the message levels that are sent to the client. | Session | Immediately | User |
commit_delay — Sets the delay in microseconds between transaction commit and flushing WAL to disk. | Session | Immediately | Superuser |
commit_siblings — Sets the minimum concurrent open transactions before performing commit_delay . | Session | Immediately | User |
config_file — Sets the server's main configuration file. | Cluster | Restart | EPAS account |
constraint_exclusion — Enables the planner to use constraints to optimize queries. | Session | Immediately | User |
cpu_index_tuple_cost — Sets the planner's estimate of the cost of processing each index entry during an index scan. | Session | Immediately | User |
cpu_operator_cost — Sets the planner's estimate of the cost of processing each operator or function call. | Session | Immediately | User |
cpu_tuple_cost — Sets the planner's estimate of the cost of processing each tuple (row). | Session | Immediately | User |
cursor_tuple_fraction — Sets the planner's estimate of the fraction of a cursor's rows to retrieve. | Session | Immediately | User |
custom_variable_classes (EPAS only) — Deprecated in EDB Postgres Advanced Server 9.2. | Cluster | Reload | EPAS account |
data_checksums — Shows whether data checksums are turned on for this cluster. | Cluster | Preset | n/a |
data_directory — Sets the server's data directory. | Cluster | Restart | EPAS account |
datestyle — Sets the display format for date and time values. | Session | Immediately | User |
db_dialect (EPAS only) |