# send_abort_for_kill

> send_abort_for_kill — Send SIGABRT not SIGKILL to stuck child processes. Observed in PG16–19 Beta 3; its last measured boot default is off 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:** “Send SIGABRT not SIGKILL to stuck child processes.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `bool` | 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 | Developer Options | Upstream classification |
| Latest boot value | `off` | off |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG16 |
| Present in | PG16–19 Beta 3 |
| Removed in | No |
| Introduction commit | [`51b5834cd53f`](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=51b5834cd53f0bd068729043b55f7da3ca6bb15f) — Provide options for postmaster to kill child processes with SIGABRT. |
| Commit date | 2022-11-21 |
| Discussion | [thread 1](https://postgr.es/m/2251016.1668797294@sss.pgh.pa.us) |

## Default history {#default-history}

| Versions | Raw `boot_val` | Unit | Human value |
| --- | --- | --- | --- |
| PG16–19 Beta 3 | `off` | — | off |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

When a child does not exit after SIGQUIT, the postmaster normally escalates to SIGKILL after five seconds. send_abort_for_kill uses SIGABRT instead so the stuck child normally writes a core dump.

SIGABRT provides forensic state but can take time and disk space, potentially delaying crash recovery. It is not guaranteed to terminate as promptly as SIGKILL in every failure mode.

PostgreSQL does not clean generated cores. OS policy and monitoring must prevent repeated stuck processes from filling storage. 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 tune production OLTP with send_abort_for_kill. Enable it only for a bounded reproduction with an owner, log/disk budget, rollback condition, and evidence-capture plan; restore the default immediately afterward. |
| OLAP | Long analytical runs can amplify send_abort_for_kill's debug overhead and artifacts. Prefer standard EXPLAIN and statistics first, and isolate any developer experiment from normal users. |
| Small nodes | Keep send_abort_for_kill at its upstream default. A small host has less spare CPU, disk, connection, and log capacity for developer instrumentation. |
{.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: PG16–19 Beta 3 unmodified; OLAP: PG16–19 Beta 3 unmodified; CRIT: PG16–19 Beta 3 unmodified; TINY: PG16–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

## Common pitfalls {#common-pitfalls}

- Leaving send_abort_for_kill 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}

[`send_abort_for_crash`](/parameters/send-abort-for-crash/) · [`remove_temp_files_after_crash`](/parameters/remove-temp-files-after-crash/) · [`log_error_verbosity`](/parameters/log-error-verbosity/) · [`data_directory`](/parameters/data-directory/)

## References {#references}

- [PostgreSQL 19 Beta 3 — send_abort_for_kill](https://www.postgresql.org/docs/19/runtime-config-developer.html#GUC-SEND-ABORT-FOR-KILL)
- [PostgreSQL 19 release notes](https://www.postgresql.org/docs/19/release-19.html)
- [Machine-readable GUC export](/data/guc.jsonl)