disk_full could not write to file “…”: No space left on device — 53100

Symptoms

PostgreSQL could not write to a file (often a temporary or WAL file) because the device is full. It raises SQLSTATE 53100 (disk_full).

• Common with large sorts/hash joins writing temp files.
• Also seen when the WAL/pg_wal directory volume fills.
• The named file indicates whether it is temp, WAL, or relation data.

What the server log shows

ERROR:  could not write to file "base/pgsql_tmp/pgsql_tmp12345.0": No space left on device

Why PostgreSQL raises this — what the manual says

Section 19.4.2 Disk (temp_file_limit):

“Specifies the maximum amount of disk space that a process can use for temporary files, such as sort and hash temporary files, or the storage file for a held cursor.”

Operations that exceed memory spill to temporary files; WAL and relations also write to disk. When the volume is full, the OS write fails and PostgreSQL reports 53100, cancelling the operation.

Common causes

• Huge sorts/hash joins spilling large temp files.
• The temp tablespace volume running out of space.
• WAL accumulation filling pg_wal.

How to fix it

1. Cap per-process temp usage with temp_file_limit.
2. Reduce data scanned/sorted; add indexes or paginate.
3. Move temp files to a larger tablespace, or expand the volume.

Related & next steps

• SQLSTATE 53100 — Disk Full (full reference)
• Message: temporary file size exceeds temp_file_limit
• Glossary: Temporary files

Reference: PostgreSQL 18 Section 19.4 “Resource Consumption”.