# autovacuum_freeze_max_age

> autovacuum_freeze_max_age — Age at which to autovacuum a table to prevent transaction ID wraparound. Observed in PG9.0–19 Beta 3; its last measured boot default is 200000000 in PG19 Beta 3, with postmaster context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
---

> [!NOTE]
> **Fact — official short description:** “Age at which to autovacuum a table to prevent transaction ID wraparound.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `integer` | Upstream pg_settings type |
| Context | `postmaster` | Requires a server restart |
| Unit | — | Raw unit |
| Range | `100000` – `2000000000` | Raw limits in the last observed version |
| Enum values | — | — for non-enum types |
| Category | Vacuuming / Automatic Vacuuming | Upstream classification |
| Latest boot value | `200000000` | 200000000 |
{.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 | `200000000` | — | 200000000 |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

Age at which to autovacuum a table to prevent transaction ID wraparound. The value is fixed when the server starts, so changing it requires a restart.

Reaching the max age forces an aggressive autovacuum even if ordinary autovacuum is disabled; a per-table override can only lower the global ceiling. Safety must be assessed across every database/table age together with long transactions and replication slots.

Monitor and change autovacuum_freeze_max_age together with vacuum_freeze_min_age, vacuum_freeze_table_age, vacuum_failsafe_age. Validate on the relevant server role and real workload, then use its postmaster 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 | Calibrate autovacuum_freeze_max_age against the oldest XID/MXID age in every database and measured vacuum completion rate. Remove long transactions, stale slots, and blocked workers; never raise ages merely to hide a backlog. |
| OLAP | Proactively VACUUM (FREEZE) newly loaded or static partitions in batch windows and reserve I/O time for full scans. Convert age budgets using peak transaction rate, not a wall-clock guess. |
| Small nodes | Upstream defaults are usually safest. A small system still needs anti-wraparound maintenance; monitor every database, not only the application database. |
{.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 | `1000000000` | different | `1000000000` |
| OLAP | `1000000000` | different | `1000000000` |
| CRIT | `1000000000` | different | `1000000000` |
| TINY | `1000000000` | different | `1000000000` |
{.full-width}

> [!CAUTION]
> **Advice — pending human review.** Fact from the current Pigsty template projection: OLTP: PG9.0–19 Beta 3 = 1000000000 (dcs); OLAP: PG9.0–19 Beta 3 = 1000000000 (dcs); CRIT: PG9.0–19 Beta 3 = 1000000000 (dcs); TINY: PG9.0–19 Beta 3 = 1000000000 (dcs). Advice, pending human review — Editorial interpretation, pending human maintainer review: the override appears intended to reduce forced anti-wraparound vacuum frequency by accepting a larger XID-age operating window; confirm it against the current Pigsty templates, hardware fixture, and operational guarantees before publication.

## Common pitfalls {#common-pitfalls}

- Converting transaction age to days without using the actual transaction rate.
- Raising the ceiling to hide blocked or underprovisioned vacuum.
- Monitoring only the current database instead of every database and table.
- Changing the global value while a table storage parameter overrides it.
- Treating reltuples and cumulative change statistics as exact real-time counts.

## Related parameters {#related-parameters}

[`vacuum_freeze_min_age`](/parameters/vacuum-freeze-min-age/) · [`vacuum_freeze_table_age`](/parameters/vacuum-freeze-table-age/) · [`vacuum_failsafe_age`](/parameters/vacuum-failsafe-age/) · [`autovacuum_multixact_freeze_max_age`](/parameters/autovacuum-multixact-freeze-max-age/) · [`vacuum_multixact_freeze_min_age`](/parameters/vacuum-multixact-freeze-min-age/) · [`vacuum_multixact_freeze_table_age`](/parameters/vacuum-multixact-freeze-table-age/)

## References {#references}

- [PostgreSQL 19 Beta 3 — autovacuum_freeze_max_age](https://www.postgresql.org/docs/19/runtime-config-vacuum.html#GUC-AUTOVACUUM-FREEZE-MAX-AGE)
- [PostgreSQL 19 release notes](https://www.postgresql.org/docs/19/release-19.html)
- [Machine-readable GUC export](/data/guc.jsonl)