# archive_command

> archive_command — Sets the shell command that will be called to archive a WAL file. Observed in PG9.0–19 Beta 3; its last measured boot default is empty string in PG19 Beta 3, with sighup context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
---

> [!NOTE]
> **Fact — official short description:** “Sets the shell command that will be called to archive a WAL file.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `string` | Upstream pg_settings type |
| Context | `sighup` | Takes effect after configuration reload |
| Unit | — | Raw unit |
| Range | — | Raw limits in the last observed version |
| Enum values | — | — for non-enum types |
| Category | Write-Ahead Log / Archiving | Upstream classification |
| Latest boot value | `""` | empty string |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG9.0 (research boundary) |
| Present in | PG9.0–19 Beta 3 |
| Removed in | No |
| Introduction commit | Not asserted: predates the PG9.0 research boundary |
| Commit date | — |
| Discussion | — |

## Default history {#default-history}

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

## How it works {#mechanism}

Sets the shell command that will be called to archive a WAL file. A configuration reload applies a new value; existing work already in flight is not retroactively changed.

The archiver expands %p to the source path and %f to the WAL file name, and considers exit status zero a durable success. A nonzero result is retried; a false success allows PostgreSQL to recycle the only local copy and silently breaks the archive chain.

Monitor and change archive_command together with archive_mode, archive_library, archive_timeout. Validate on the relevant server role and real workload, then use its sighup context to choose session change, reload, or restart; a historical boot default is not the current effective value.

## Tuning advice {#tuning-advice}

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

| Workload | Guidance |
| --- | --- |
| OLTP | Manage archive_command as part of the backup/restore protocol: the command or module must be idempotent, fail visibly, and be verified by restoring from the real archive—not merely by exit status. |
| OLAP | Provision archive throughput and capacity for bulk-load WAL peaks. If archiving falls behind, throttle the job and alert; never hide backlog with false success or aggressive cleanup. |
| Small nodes | Enable it only for a defined PITR requirement and use a mature backup tool. Keep rebuildable instances simple, but never install a no-op command that creates the illusion of a backup. |
{.full-width}

## Pigsty {#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 | `pgbackrest --stanza=fixture archive-push %p` | different | `'pgbackrest --stanza={{ pg_cluster }} archive-push %p'` |
| OLAP | `pgbackrest --stanza=fixture archive-push %p` | different | `'pgbackrest --stanza={{ pg_cluster }} archive-push %p'` |
| CRIT | `pgbackrest --stanza=fixture archive-push %p` | different | `'pgbackrest --stanza={{ pg_cluster }} archive-push %p'` |
| TINY | `pgbackrest --stanza=fixture archive-push %p` | different | `'pgbackrest --stanza={{ pg_cluster }} archive-push %p'` |
{.full-width}

> [!CAUTION]
> **Advice — pending human review.** Fact from the current Pigsty template projection: OLTP: PG9.0–19 Beta 3 = pgbackrest --stanza=fixture archive-push %p (dcs); OLAP: PG9.0–19 Beta 3 = pgbackrest --stanza=fixture archive-push %p (dcs); CRIT: PG9.0–19 Beta 3 = pgbackrest --stanza=fixture archive-push %p (dcs); TINY: PG9.0–19 Beta 3 = pgbackrest --stanza=fixture archive-push %p (dcs). Advice, pending human review — Editorial interpretation, pending human maintainer review: the override appears intended to bind archiving to the pgBackRest stanza used by Pigsty for PITR; confirm it against the current Pigsty templates, hardware fixture, and operational guarantees before publication.

## Common pitfalls {#common-pitfalls}

- Returning success before the archive copy is durable or verified.
- Failing to quote %p/%f safely in a shell command.
- Letting repeated failures fill pg_wal and stop the server.
- Confusing pg_settings base units with human-readable configuration units.
- Benchmarking throughput without a crash-recovery and archive-restore test.

## Related parameters {#related-parameters}

[`archive_mode`](/parameters/archive-mode/) · [`archive_library`](/parameters/archive-library/) · [`archive_timeout`](/parameters/archive-timeout/) · [`archive_cleanup_command`](/parameters/archive-cleanup-command/) · [`restore_command`](/parameters/restore-command/) · [`recovery_end_command`](/parameters/recovery-end-command/)

## References {#references}

- [PostgreSQL 19 Beta 3 — archive_command](https://www.postgresql.org/docs/19/runtime-config-wal.html#GUC-ARCHIVE-COMMAND)
- [PostgreSQL 19 release notes](https://www.postgresql.org/docs/19/release-19.html)
- [Machine-readable GUC export](/data/guc.jsonl)