# autovacuum_analyze_scale_factor

> autovacuum_analyze_scale_factor — Number of tuple inserts, updates, or deletes prior to analyze as a fraction of reltuples. Observed in PG9.0–19 Beta 3; its last measured boot default is 0.1 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:** “Number of tuple inserts, updates, or deletes prior to analyze as a fraction of reltuples.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `real` | Upstream pg_settings type |
| Context | `sighup` | Takes effect after configuration reload |
| Unit | — | Raw unit |
| Range | `0` – `100` | Raw limits in the last observed version |
| Enum values | — | — for non-enum types |
| Category | Vacuuming / Automatic Vacuuming | Upstream classification |
| Latest boot value | `0.1` | 0.1 |
{.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 | `0.1` | — | 0.1 |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

Number of tuple inserts, updates, or deletes prior to analyze as a fraction of reltuples. A configuration reload applies a new value; existing work already in flight is not retroactively changed.

The automatic-ANALYZE trigger is autovacuum_analyze_threshold plus autovacuum_analyze_scale_factor times pg_class.reltuples; inserts, updates, and deletes feed the cumulative counter. Per-table storage parameters can override the global values, and the statistics are eventually consistent estimates.

Monitor and change autovacuum_analyze_scale_factor together with autovacuum_analyze_threshold, default_statistics_target, track_counts. 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 | Tune autovacuum_analyze_scale_factor from table size, change rate, and maintenance SLA, using per-table thresholds for large/hot relations. Observe trigger intervals, dead tuples, and ANALYZE/VACUUM duration. |
| OLAP | Run explicit ANALYZE/VACUUM after bulk loads instead of waiting only for proportional triggers; plan freezing and visibility-map advancement separately for append-only partitions. |
| Small nodes | Start with upstream or the measured Pigsty matrix value. Fixed thresholds dominate on small tables; after changes, confirm worker and I/O headroom. |
{.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 | `0.04` | different | `0.04` |
| OLAP | `0.04` | different | `0.04` |
| CRIT | `0.04` | different | `0.04` |
| TINY | Unmodified | — | — |
{.full-width}

> [!CAUTION]
> **Advice — pending human review.** Fact from the current Pigsty template projection: OLTP: PG9.0–19 Beta 3 = 0.04 (dcs); OLAP: PG9.0–19 Beta 3 = 0.04 (dcs); CRIT: PG9.0–19 Beta 3 = 0.04 (dcs); TINY: PG9.0–19 Beta 3 unmodified. Advice, pending human review — Editorial interpretation, pending human maintainer review: the override appears intended to refresh planner statistics earlier on growing production tables; confirm it against the current Pigsty templates, hardware fixture, and operational guarantees before publication.

## Common pitfalls {#common-pitfalls}

- Changing the global value while a table storage parameter overrides it.
- Treating reltuples and cumulative change statistics as exact real-time counts.
- Blaming a threshold without checking long transactions, replication slots, and worker saturation.
- Buying short-term quiet by deferring maintenance until wraparound failsafe activates.

## Related parameters {#related-parameters}

[`autovacuum_analyze_threshold`](/parameters/autovacuum-analyze-threshold/) · [`default_statistics_target`](/parameters/default-statistics-target/) · [`track_counts`](/parameters/track-counts/) · [`autovacuum`](/parameters/autovacuum/) · [`autovacuum_freeze_max_age`](/parameters/autovacuum-freeze-max-age/) · [`autovacuum_max_workers`](/parameters/autovacuum-max-workers/)

## References {#references}

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