PostgreSQL - Advanced parameters references

Last updated 6th February 2023

Objective

This guide lists all the supported advanced parameters that allow you to configure your Public Cloud Databases for PostgreSQL according to your use cases.

Requirements

Instructions

The management of advanced parameters is not supported via Terraform.

Using the OVHcloud Control Panel

Please refer to this guide to find out how to change your advanced parameters from the OVHcloud Control Panel.

Using API

Please refer to this guide to find out how to change your advanced parameters from the OVHcloud API.

Advanced parameters for PostgreSQL

Below you can find a summary of every configuration option available for PostgreSQL service:

General parameters
Parameter pg.autovacuum_analyze_scale_factor
Value type double
Minumum 0
Maximum 1
Values
Description Specifies a fraction of the table size to add to autovacuum_analyze_threshold when deciding whether to trigger an ANALYZE. The default is 0.2 (20% of table size)
Parameter pg.autovacuum_analyze_threshold
Value type long
Minumum 0
Maximum 2147483647
Values
Description Specifies the minimum number of inserted, updated or deleted tuples needed to trigger an ANALYZE in any one table. The default is 50 tuples.
Parameter pg.autovacuum_freeze_max_age
Value type long
Minumum 200000000
Maximum 1500000000
Values
Description Specifies the maximum age (in transactions) that a table's pg_class.relfrozenxid field can attain before a VACUUM operation is forced to prevent transaction ID wraparound within the table. Note that the system will launch autovacuum processes to prevent wraparound even when autovacuum is otherwise disabled. This parameter will cause the server to be restarted.
Parameter pg.autovacuum_max_workers
Value type long
Minumum 1
Maximum 20
Values
Description Specifies the maximum number of autovacuum processes (other than the autovacuum launcher) that may be running at any one time. The default is three. This parameter can only be set at server start.
Parameter pg.autovacuum_naptime
Value type long
Minumum 1
Maximum 86400
Values
Description Specifies the minimum delay between autovacuum runs on any given database. The delay is measured in seconds, and the default is one minute
Parameter pg.autovacuum_vacuum_cost_delay
Value type long
Minumum -1
Maximum 100
Values
Description Specifies the cost delay value that will be used in automatic VACUUM operations. If -1 is specified, the regular vacuum_cost_delay value will be used. The default value is 20 milliseconds
Parameter pg.autovacuum_vacuum_cost_limit
Value type long
Minumum -1
Maximum 10000
Values
Description Specifies the cost limit value that will be used in automatic VACUUM operations. If -1 is specified (which is the default), the regular vacuum_cost_limit value will be used.
Parameter pg.autovacuum_vacuum_scale_factor
Value type double
Minumum 0
Maximum 1
Values
Description Specifies a fraction of the table size to add to autovacuum_vacuum_threshold when deciding whether to trigger a VACUUM. The default is 0.2 (20% of table size)
Parameter pg.autovacuum_vacuum_threshold
Value type long
Minumum 0
Maximum 2147483647
Values
Description Specifies the minimum number of updated or deleted tuples needed to trigger a VACUUM in any one table. The default is 50 tuples
Parameter pg.bgwriter_delay
Value type long
Minumum 10
Maximum 10000
Values
Description Specifies the delay between activity rounds for the background writer in milliseconds. Default is 200.
Parameter pg.bgwriter_flush_after
Value type long
Minumum 0
Maximum 2048
Values
Description Whenever more than bgwriter_flush_after bytes have been written by the background writer, attempt to force the OS to issue these writes to the underlying storage. Specified in kilobytes, default is 512. Setting of 0 disables forced writeback.
Parameter pg.bgwriter_lru_maxpages
Value type long
Minumum 0
Maximum 1073741823
Values
Description In each round, no more than this many buffers will be written by the background writer. Setting this to zero disables background writing. Default is 100.
Parameter pg.bgwriter_lru_multiplier
Value type double
Minumum 0
Maximum 10
Values
Description The average recent need for new buffers is multiplied by bgwriter_lru_multiplier to arrive at an estimate of the number that will be needed during the next round, (up to bgwriter_lru_maxpages). 1.0 represents a “just in time” policy of writing exactly the number of buffers predicted to be needed. Larger values provide some cushion against spikes in demand, while smaller values intentionally leave writes to be done by server processes. The default is 2.0.
Parameter pg.deadlock_timeout
Value type long
Minumum 500
Maximum 1800000
Values
Description This is the amount of time, in milliseconds, to wait on a lock before checking to see if there is a deadlock condition.
Parameter pg.default_toast_compression
Value type string
Minumum
Maximum
Values "lz4", "pglz"
Description Specifies the default TOAST compression method for values of compressible columns (the default is lz4).
Parameter pg.idle_in_transaction_session_timeout
Value type long
Minumum 0
Maximum 604800000
Values
Description Time out sessions with open transactions after this number of milliseconds
Parameter pg.jit
Value type boolean
Minumum
Maximum
Values
Description Controls system-wide use of Just-in-Time Compilation (JIT).
Parameter pg.log_autovacuum_min_duration
Value type long
Minumum -1
Maximum 2147483647
Values
Description Causes each action executed by autovacuum to be logged if it ran for at least the specified number of milliseconds. Setting this to zero logs all autovacuum actions. Minus-one (the default) disables logging autovacuum actions.
Parameter pg.log_error_verbosity
Value type string
Minumum
Maximum
Values "DEFAULT", "TERSE", "VERBOSE"
Description Controls the amount of detail written in the server log for each message that is logged.
Parameter pg.log_line_prefix
Value type string
Minumum
Maximum
Values "'%m [%p] %q[user=%u,db=%d,app=%a] '", "'%t [%p]: [%l-1] user=%u,db=%d,app=%a,client=%h '", "'pid=%p,user=%u,db=%d,app=%a,client=%h '"
Description Choose from one of the available log-formats. These can support popular log analyzers like pgbadger, pganalyze etc.
Parameter pg.log_min_duration_statement
Value type long
Minumum -1
Maximum 86400000
Values
Description Log statements that take more than this number of milliseconds to run, -1 disables
Parameter pg.log_temp_files
Value type long
Minumum -1
Maximum 2147483647
Values
Description Log statements for each temporary file created larger than this number of kilobytes, -1 disables
Parameter pg.max_files_per_process
Value type long
Minumum 1000
Maximum 4096
Values
Description PostgreSQL maximum number of files that can be open per process
Parameter pg.max_locks_per_transaction
Value type long
Minumum 64
Maximum 6400
Values
Description PostgreSQL maximum locks per transaction
Parameter pg.max_logical_replication_workers
Value type long
Minumum 4
Maximum 64
Values
Description PostgreSQL maximum logical replication workers (taken from the pool of max_parallel_workers)
Parameter pg.max_parallel_workers
Value type long
Minumum 0
Maximum 96
Values
Description Sets the maximum number of workers that the system can support for parallel queries
Parameter pg.max_parallel_workers_per_gather
Value type long
Minumum 0
Maximum 96
Values
Description Sets the maximum number of workers that can be started by a single Gather or Gather Merge node
Parameter pg.max_pred_locks_per_transaction
Value type long
Minumum 64
Maximum 5120
Values
Description PostgreSQL maximum predicate locks per transaction
Parameter pg.max_prepared_transactions
Value type long
Minumum 0
Maximum 10000
Values
Description PostgreSQL maximum prepared transactions
Parameter pg.max_replication_slots
Value type long
Minumum 8
Maximum 64
Values
Description PostgreSQL maximum replication slots
Parameter pg.max_slot_wal_keep_size
Value type long
Minumum -1
Maximum 2147483647
Values
Description PostgreSQL maximum WAL size (MB) reserved for replication slots. Default is -1 (unlimited). wal_keep_size minimum WAL size setting takes precedence over this.
Parameter pg.max_stack_depth
Value type long
Minumum 2097152
Maximum 6291456
Values
Description Maximum depth of the stack in bytes
Parameter pg.max_standby_archive_delay
Value type long
Minumum 1
Maximum 43200000
Values
Description Max standby archive delay in milliseconds
Parameter pg.max_standby_streaming_delay
Value type long
Minumum 1
Maximum 43200000
Values
Description Max standby streaming delay in milliseconds
Parameter pg.max_wal_senders
Value type long
Minumum 20
Maximum 64
Values
Description PostgreSQL maximum WAL senders
Parameter pg.max_worker_processes
Value type long
Minumum 8
Maximum 96
Values
Description Sets the maximum number of background processes that the system can support
Parameter pg.pg_partman_bgw.interval
Value type long
Minumum 3600
Maximum 604800
Values
Description Sets the time interval to run pg_partman's scheduled tasks
Parameter pg.pg_partman_bgw.role
Value type string
Minumum
Maximum
Values
Description Controls which role to use for pg_partman's scheduled background tasks.
Parameter pg.pg_stat_monitor.pgsm_enable_query_plan
Value type boolean
Minumum
Maximum
Values
Description Enables or disables query plan monitoring
Parameter pg.pg_stat_monitor.pgsm_max_buckets
Value type long
Minumum 1
Maximum 10
Values
Description Sets the maximum number of buckets
Parameter pg.temp_file_limit
Value type long
Minumum -1
Maximum 2147483647
Values
Description PostgreSQL temporary file limit in KiB, -1 for unlimited
Parameter pg.timezone
Value type string
Minumum
Maximum
Values
Description PostgreSQL service timezone
Parameter pg.track_activity_query_size
Value type long
Minumum 1024
Maximum 10240
Values
Description Specifies the number of bytes reserved to track the currently executing command for each active session.
Parameter pg.track_commit_timestamp
Value type string
Minumum
Maximum
Values "off", "on"
Description Record commit time of transactions.
Parameter pg.track_functions
Value type string
Minumum
Maximum
Values "all", "none", "pl"
Description Enables tracking of function call counts and time used.
Parameter pg.track_io_timing
Value type string
Minumum
Maximum
Values "off", "on"
Description Enables timing of database I/O calls. This parameter is off by default, because it will repeatedly query the operating system for the current time, which may cause significant overhead on some platforms.
Parameter pg.wal_sender_timeout
Value type long
Minumum
Maximum
Values
Description Terminate replication connections that are inactive for longer than this amount of time, in milliseconds. Setting this value to zero disables the timeout.
Parameter pg.wal_writer_delay
Value type long
Minumum 10
Maximum 200
Values
Description WAL flush interval in milliseconds. Note that setting this value to lower than the default 200ms may negatively impact performance
Parameter pgbouncer.autodb_idle_timeout
Value type long
Minumum 0
Maximum 86400
Values
Description The number of seconds after which - if unused - the automatically created database pools are freed. If set to 0, then timeout is disabled.
Parameter pgbouncer.autodb_max_db_connections
Value type long
Minumum 0
Maximum 2147483647
Values
Description The overall maximum number of server connections per database (regardless of user). Setting it to 0 means it is unlimited.
Parameter pgbouncer.autodb_pool_mode
Value type string
Minumum
Maximum
Values "session", "statement", "transaction"
Description The PgBouncer pool mode:
- with session, the server is released back to the pool after the client disconnects
- with transaction, the server is released back to the pool after the transaction finishes
- with statement the server is released back to the pool after the query finishes (transactions spanning multiple statements are disallowed in this mode).
The default value is: session.
A valid range is: session, transaction, statement
Parameter pgbouncer.autodb_pool_size
Value type long
Minumum 0
Maximum 10000
Values
Description When set to non-zero, it automatically creates a pool of the specified size per user, provided that the pool doesn’t exist.
Parameter pgbouncer.min_pool_size
Value type long
Minumum 0
Maximum 10000
Values
Description Adds more server connections to the pool if the pool connection number is smaller than this number. It improves the behavior when the usual load comes back suddenly after a period of total inactivity. The value is capped at the pool size.
Parameter pgbouncer.server_idle_timeout
Value type long
Minumum 0
Maximum 86400
Values
Description The amount of time in seconds after which the server connection is dropped. If set to 0, then timeout is disabled.
Parameter pgbouncer.server_lifetime
Value type long
Minumum 60
Maximum 86400
Values
Description The amount of time after which the pooler closes any unused server connection.
Parameter pgbouncer.server_reset_query_always
Value type boolean
Minumum
Maximum
Values
Description Runs server_reset_query (DISCARD ALL) in all pooling modes.
Parameter timescaledb.max_background_workers
Value type long
Minumum 1
Maximum 4096
Values
Description The number of background workers for timescaledb operations. You should configure this setting to the sum of your number of databases and the total number of concurrent background workers you want running at any given point in time.

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