# trace_recovery_messages

> trace_recovery_messages — Enables logging of recovery-related debugging information. Observed in PG9.0–16; its last measured boot default is log in PG16, with sighup context. It was removed in PG17.
---

> [!NOTE]
> **Fact — official short description:** “Enables logging of recovery-related debugging information.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `enum` | Upstream pg_settings type |
| Context | `sighup` | Takes effect after configuration reload |
| Unit | — | Raw unit |
| Range | — | Raw limits in the last observed version |
| Enum values | `debug5`, `debug4`, `debug3`, `debug2`, `debug1`, `log`, `notice`, `warning`, `error` | — for non-enum types |
| Category | Developer Options | Upstream classification |
| Latest boot value | `log` | log |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG9.0 (research boundary) |
| Present in | PG9.0–16 |
| Removed in | PG17 |
| Introduction commit | Not asserted: predates the PG9.0 research boundary |
| Commit date | — |
| Discussion | — |

## Default history {#default-history}

| Versions | Raw `boot_val` | Unit | Human value |
| --- | --- | --- | --- |
| PG9.0–16 | `log` | — | log |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

Through PG16, trace_recovery_messages remapped recovery DEBUG messages at or above a chosen severity to LOG, making normally hidden recovery internals visible during testing.

It changed message visibility, not recovery decisions, WAL replay order, or durability. Verbose recovery logging could be extremely large and timing-sensitive.

PostgreSQL 17 removed the parameter. Upgrade configurations must delete it; current recovery diagnosis should use supported logging, progress, and WAL inspection facilities. Its SIGHUP context allows configuration reload without a server restart.

## Tuning advice {#tuning-advice}

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

| Workload | Guidance |
| --- | --- |
| OLTP | Do not configure trace_recovery_messages on current PostgreSQL. Remove it during upgrades; use any named successor only for the same controlled developer test, not as a production default. |
| OLAP | Analytical workload does not justify retaining the removed trace_recovery_messages. Diagnose current versions with supported EXPLAIN, logs, or the documented replacement. |
| Small nodes | Delete trace_recovery_messages from modern configurations. Unknown-parameter startup failure and diagnostic overhead outweigh any historical use. |
{.full-width}

## Pigsty {#pigsty}

Values use the fixed 8-vCPU, 32-GiB, 100-GiB SSD fixture and render the current Pigsty templates for PG16; 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: PG9.0–16 unmodified; OLAP: PG9.0–16 unmodified; CRIT: PG9.0–16 unmodified; TINY: PG9.0–16 unmodified. No Pigsty-specific rationale is inferred from an absent override.

## Common pitfalls {#common-pitfalls}

- Leaving trace_recovery_messages enabled after the bounded diagnostic or recovery task.
- Running the experiment on the only copy of production data.
- Underestimating log, core-file, temporary-file, WAL, CPU, or connection-slot amplification.
- Treating a server that merely starts or completes a query as proof that data and behavior are correct.

## Related parameters {#related-parameters}

[`log_min_messages`](/parameters/log-min-messages/) · [`restore_command`](/parameters/restore-command/) · [`recovery_min_apply_delay`](/parameters/recovery-min-apply-delay/) · [`wal_consistency_checking`](/parameters/wal-consistency-checking/)

## References {#references}

- [PostgreSQL 16 — trace_recovery_messages](https://www.postgresql.org/docs/16/runtime-config-developer.html#GUC-TRACE-RECOVERY-MESSAGES)
- [Machine-readable GUC export](/data/guc.jsonl)