syslog_sequence_numbers

syslog_sequence_numbers is the PostgreSQL setting that adds sequence number to syslog messages to avoid duplicate suppression.

Note

Fact — official short description: “Add sequence number to syslog messages to avoid duplicate suppression.”

Identity

Type , Valuebool: Upstream pg_settings type
Context , Valuesighup: Takes effect after configuration reload
Unit , Value—: Raw unit
Range , Value—: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueReporting and Logging / Where to Log: Upstream classification
Latest boot value , Valueon: on

Lifecycle

Fact	Value
First observed	PG9.6
Present in	PG9.6–19 Beta 3
Removed in	No
Introduction commit	`f4c454e9ba52` — Add syslog_sequence_numbers parameter
Commit date	2016-02-26
Discussion	—

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG9.6–19 Beta 3	`on`	—	on

How it works

syslog_sequence_numbers adds sequence number to syslog messages to avoid duplicate suppression. A monotonically increasing sequence prefix prevents some syslog implementations from collapsing repeated messages and helps detect gaps.

syslog_sequence_numbers is a SIGHUP-context setting: a configuration reload activates the new server value without a restart; subsequent operations that consult it use the refreshed value.

It is active only when syslog appears in log_destination, after which the facility, ident, sequence, splitting, host daemon, and remote receiver jointly define record delivery.

Tuning advice

Tip

Advice. These are workload-specific starting points and must be validated with measurements.

Workload	Guidance
OLTP	Set syslog_sequence_numbers to match the receiving syslog daemon’s routing, framing, deduplication, and message-size contract; validate failover and backpressure with the real collector.
OLAP	Test syslog_sequence_numbers under bursty analytical messages and multiline plans so splitting or receiver limits do not destroy record boundaries.
Small nodes	Prefer the host’s established syslog convention for syslog_sequence_numbers; avoid parallel local-file retention unless it has an explicit purpose and size limit.

Pigsty

Values use the fixed 8-vCPU, 32-GiB, 100-GiB SSD fixture and render the current Pigsty templates for PG19 Beta 3; this does not assert current Pigsty support for that historical or beta release.

Template	Effective value	Versus upstream boot	Source expression
OLTP	Unmodified	—	—
OLAP	Unmodified	—	—
CRIT	Unmodified	—	—
TINY	Unmodified	—	—

Caution

Advice — pending human review. Fact from the current Pigsty template projection: OLTP: PG9.6–19 Beta 3 unmodified; OLAP: PG9.6–19 Beta 3 unmodified; CRIT: PG9.6–19 Beta 3 unmodified; TINY: PG9.6–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Editing syslog_sequence_numbers without reloading configuration and verifying the effective value and subsequent behavior.
Changing PostgreSQL framing or identifiers without testing the host daemon and remote receiver as one pipeline.
Assuming syslog preserves unlimited message size, multiline boundaries, ordering, or repeated records by default.
Changing syslog_sequence_numbers globally without a rollback plan and a client or operational compatibility test.

log_destination · syslog_facility · syslog_ident · syslog_split_messages · logging_collector