disk_full Disk Full — SQLSTATE 53100

The server could not write because the disk or tablespace is full.

• The error is written to the server log and returned to the client carrying SQLSTATE 53100.
• Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
• PL/pgSQL can trap it by name: EXCEPTION WHEN disk_full THEN.

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Most often seen under load or on under-provisioned servers; correlate it with system metrics (CPU, memory, disk, connection count) at the time of the error.

A write failed for lack of free space on the data, WAL, or temp directory.

Common causes:

• Ordinary data growth.
• WAL piling up because archiving is failing or a replication slot is stale.
• Large temp files from big sorts or joins.
• Log files filling the volume.

Steps to resolve 53100:

1. Free space immediately: remove old logs/temp files or expand the volume.
2. Check WAL bloat — a failing archive_command or an inactive replication slot prevents cleanup; fix archiving or drop the unused slot with pg_drop_replication_slot.
3. Reduce temp usage by tuning queries and work_mem, or set temp_file_limit.
4. Alert on disk usage well before the volume fills.

Reference: PostgreSQL error codes — Class 53 (Insufficient Resources).