# wal_sender_timeout

> wal_sender_timeout — Sets the maximum time to wait for WAL replication. Observed in PG9.3–19 Beta 3; its last measured boot default is 1 min in PG19 Beta 3, with user context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
---

> [!NOTE]
> **Fact — official short description:** “Sets the maximum time to wait for WAL replication.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `integer` | Upstream pg_settings type |
| Context | `user` | Settable by an ordinary user |
| Unit | `ms` | Raw unit |
| Range | `0` – `2147483647` | Raw limits in the last observed version |
| Enum values | — | — for non-enum types |
| Category | Replication / Sending Servers | Upstream classification |
| Latest boot value | `60000` | 1 min |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG9.3 |
| Present in | PG9.3–19 Beta 3 |
| Removed in | No |
| Introduction commit | [`6f60fdd7015b`](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=6f60fdd7015b032bf49273c99f80913d57eac284) — Improve replication connection timeouts. |
| Commit date | 2012-10-11 |
| Discussion | — |

## Default history {#default-history}

| Versions | Raw `boot_val` | Unit | Human value |
| --- | --- | --- | --- |
| PG9.3–19 Beta 3 | `60000` | `ms` | 1 min |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

Sets the maximum time to wait for WAL replication. It can be changed at session scope, so different sessions may observe different behavior.

A WAL sender terminates a replication connection that remains inactive for this interval. Each sender session may use a location-appropriate value; zero disables detection and very short settings cause churn across high-latency links.

Monitor and change wal_sender_timeout together with max_wal_senders, max_replication_slots, wal_level. Validate on the relevant server role and real workload, then use its user 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 | Size wal_sender_timeout from topology, failover roles, slot/subscription count, and reconnect headroom. Test worst-case primary latency, standby replay, and disk retention before production. |
| OLAP | Read standbys and logical subscribers often see long queries or large transactions. Put explicit bounds on replay/apply and monitor lag, worker saturation, slot restart_lsn, and conflict cancellations. |
| Small nodes | Configure only replication capacity that is actually used. Even a small topology needs bounded timeouts and slot lifecycle; unlimited retention is not reliability. |
{.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 | Unmodified | — | — |
| OLAP | Unmodified | — | — |
| CRIT | Unmodified | — | — |
| TINY | Unmodified | — | — |
{.full-width}

> [!CAUTION]
> **Advice — pending human review.** Fact from the current Pigsty template projection: OLTP: PG9.3–19 Beta 3 unmodified; OLAP: PG9.3–19 Beta 3 unmodified; CRIT: PG9.3–19 Beta 3 unmodified; TINY: PG9.3–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

## Common pitfalls {#common-pitfalls}

- Changing it on the wrong primary, standby, sender, or subscriber role.
- Watching only configured bytes/time instead of actual lag, slot position, and worker state.
- Failing over to a node that lacks the old primary's capacity or prerequisites.
- Using infinite waits or WAL retention to hide a failed consumer.

## Related parameters {#related-parameters}

[`max_wal_senders`](/parameters/max-wal-senders/) · [`max_replication_slots`](/parameters/max-replication-slots/) · [`wal_level`](/parameters/wal-level/) · [`primary_conninfo`](/parameters/primary-conninfo/) · [`max_slot_wal_keep_size`](/parameters/max-slot-wal-keep-size/) · [`wal_receiver_status_interval`](/parameters/wal-receiver-status-interval/)

## References {#references}

- [PostgreSQL 19 Beta 3 — wal_sender_timeout](https://www.postgresql.org/docs/19/runtime-config-replication.html#GUC-WAL-SENDER-TIMEOUT)
- [PostgreSQL 19 release notes](https://www.postgresql.org/docs/19/release-19.html)
- [Machine-readable GUC export](/data/guc.jsonl)