# silent_mode

> silent_mode — Runs the server silently. Observed in PG9.0–9.1; its last measured boot default is off in PG9.1, with postmaster context. It was removed in PG9.2.
---

> [!NOTE]
> **Fact — official short description:** “Runs the server silently.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `bool` | Upstream pg_settings type |
| Context | `postmaster` | Requires a server restart |
| Unit | — | Raw unit |
| Range | — | Raw limits in the last observed version |
| Enum values | — | — for non-enum types |
| Category | Reporting and Logging / Where to Log | Upstream classification |
| Latest boot value | `off` | off |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG9.0 (research boundary) |
| Present in | PG9.0–9.1 |
| Removed in | PG9.2 |
| Introduction commit | Not asserted: predates the PG9.0 research boundary |
| Commit date | — |
| Discussion | — |

## Default history {#default-history}

| Versions | Raw `boot_val` | Unit | Human value |
| --- | --- | --- | --- |
| PG9.0–9.1 | `off` | — | off |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

PostgreSQL describes silent_mode as follows: “Runs the server silently.” The value is fixed when the server starts, so changing it requires a controlled restart. The atlas measures it in PG9.0–9.1; boot_val is the compiled or initialized baseline, not proof of a running cluster's effective setting.

Silent mode was an early background-server convenience that redirected or suppressed terminal-facing output. It was removed in PostgreSQL 9.2; service managers and PostgreSQL's logging_collector, log_destination, and log_directory settings now provide explicit process and log ownership.

Read it together with logging_collector, log_destination, log_directory, log_filename. Check SHOW and pg_settings on the target server, verify the source and pending_restart fields, and compare workload, logs, and resource metrics before and after any change.

## Tuning advice {#tuning-advice}

> [!TIP]
> **Advice.** These are workload-specific starting points and must be validated with measurements.

| Workload | Guidance |
| --- | --- |
| OLTP | Do not add this retired name to a current OLTP configuration. Translate its intent to the documented successor, test the migration under connection and write concurrency, and remove stale automation that still emits it. |
| OLAP | For an upgrade or analytical estate, inventory every generated configuration before cutover. Map the old control to its successor and compare plans, throughput, WAL, or logging behavior rather than assuming the old numeric value is portable. |
| Small nodes | Delete the obsolete override after recording why it existed. On a small node, prefer the successor's default until measurements justify a new value; an unknown startup parameter can otherwise stop the server. |
{.full-width}

## Pigsty {#pigsty}

Values use the fixed 8-vCPU, 32-GiB, 100-GiB SSD fixture and render the current Pigsty templates for PG9.1; 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 | — | — |
{.full-width}

> [!CAUTION]
> **Advice — pending human review.** Fact from the current Pigsty template projection: OLTP: PG9.0–9.1 unmodified; OLAP: PG9.0–9.1 unmodified; CRIT: PG9.0–9.1 unmodified; TINY: PG9.0–9.1 unmodified. No Pigsty-specific rationale is inferred from an absent override.

## Common pitfalls {#common-pitfalls}

- Treating the measured boot_val for silent_mode as proof of the effective value on an initialized or managed cluster.
- Applying a change as though it were immediate while pg_settings reports postmaster context.
- Changing this setting in isolation without checking the linked limits, observability, and rollback path.
- Copying the removed name into a modern postgresql.conf instead of migrating to its documented successor.

## Related parameters {#related-parameters}

[`logging_collector`](/parameters/logging-collector/) · [`log_destination`](/parameters/log-destination/) · [`log_directory`](/parameters/log-directory/) · [`log_filename`](/parameters/log-filename/)

## References {#references}

- [PostgreSQL 9.1 — silent_mode](https://www.postgresql.org/docs/9.1/runtime-config-logging.html#GUC-SILENT-MODE)
- [Machine-readable GUC export](/data/guc.jsonl)