# 58000 — system_error

> Source-backed reference entry for PostgreSQL SQLSTATE 58000.
---

# 58000

## At a glance {#at-a-glance}
`58000` is the system-error condition. In the fixed backend path, `pg_promote` creates the promotion signal file and then calls `kill(PostmasterPid, SIGUSR1)`; a failed signal reports ERROR with the operating-system text substituted for `%m`.

<!-- BEGIN SQLSTATE FACTS: generated by scripts/generate.py; do not edit -->

| Field | Value |
| --- | --- |
| SQLSTATE | `58000` |
| Condition | `system_error` |
| Status | `active` |
| Known present by | `9.2.0` |
| Locked snapshots | `9.2.24, 9.3.25, 9.4.26, 9.5.25, 9.6.24, 10.23, 11.22, 12.22, 13.23, 14.24, 15.19, 16.15, 17.11, 18.6, 19beta3` |
| Macros | `ERRCODE_SYSTEM_ERROR` |
| Aliases | `—` |

<!-- source facts: data/errcodes/58000.json -->
<!-- END SQLSTATE FACTS -->

## Meaning {#meaning}
The representative backend primary is exactly `failed to send signal to postmaster: %m`. The code unlinks the promotion signal file before raising ERROR, so the failed system call is part of a postmaster-notification path, not a user value or SQL syntax failure. The shared `common/exec.c` source uses a `log_error` macro that has two compile-time branches. In a non-FRONTEND build it expands to `ereport(LOG, (errcodefn, errmsg_internal(...)))`; in a FRONTEND build it ignores the `errcode()` argument and prints the formatted text to stderr. Thus the frontend utility message is not proof of a client-protocol `58000` diagnostic or a client transaction abort. The separate `pg_log_error` macro in `common/logging.h` maps to `PG_LOG_ERROR`, but `pclose_check()` does not call that macro.

## Messages {#messages}

- Backend `pg_promote` signal path: primary `failed to send signal to postmaster: %m`, severity ERROR. The expanded text depends on the OS `errno` at the failed `kill()` call.
- Shared `pclose_check()` source: the call-site template is `%s() failed: %m`; with `pclose()` it expands to `pclose() failed: <OS text>`. Non-FRONTEND builds log it through `ereport(LOG)` with the supplied `ERRCODE_SYSTEM_ERROR`; FRONTEND builds ignore that code and print to stderr, so this is not a client-protocol `58000` path.

## Diagnosis {#diagnosis}
Preserve the full primary after `%m` expansion, the operation (promotion signal, `pclose`, or another system helper), process identity, and server or utility log context. For backend `pg_promote`, inspect the postmaster PID, signal permissions/process liveness, and the OS error. Do not replace the OS-specific cause with a generic disk, permission, or process diagnosis without the actual errno. The SQLSTATE alone does not establish transaction outcome.

## Response {#response}
Correct the operating-system condition identified by the expanded message, then verify postmaster/server health before retrying the operation. A backend ERROR normally aborts the current explicit transaction, so send `ROLLBACK` or `ROLLBACK TO SAVEPOINT` before continuing; in autocommit, retry only after the cause is fixed. A frontend log from `pclose_check` has its utility's own control flow and does not call for a SQL transaction rollback. If the connection was lost, reconnect after readiness and verify business effects.

## Versions {#versions}
The locked catalogue records this condition from 9.2.0; that boundary does not prove the exact implementation-introduction version. Fixed source coverage is PostgreSQL 18.6.

## Related {#related}
[`57P01`](../57p01/), [`57P02`](../57p02/), [`XX000`](../xx000/)

## Sources {#sources}
[`src/backend/access/transam/xlogfuncs.c#L702-708`](https://github.com/postgres/postgres/blob/724edf9bde9d356724ad384a2e196edc3c9f80f7/src/backend/access/transam/xlogfuncs.c#L702)

[`src/common/exec.c#L52-70`](https://github.com/postgres/postgres/blob/724edf9bde9d356724ad384a2e196edc3c9f80f7/src/common/exec.c#L52)

[`src/common/exec.c#L391-412`](https://github.com/postgres/postgres/blob/724edf9bde9d356724ad384a2e196edc3c9f80f7/src/common/exec.c#L391)

[`src/include/common/logging.h#L106-110`](https://github.com/postgres/postgres/blob/724edf9bde9d356724ad384a2e196edc3c9f80f7/src/include/common/logging.h#L106)

The structured [evidence record](../data/evidence/58000.json) records the backend and frontend/common message boundaries.