out_of_memory Out Of Memory — SQLSTATE 53200

The server could not allocate memory for the operation.

• The error is written to the server log and returned to the client carrying SQLSTATE 53200.
• 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 out_of_memory 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 backend requested more memory than the OS would give — often during large sorts/hashes or with many concurrent connections.

Common causes:

• work_mem too high multiplied across many nodes and connections.
• A very large hash or sort.
• A memory leak in an extension.
• OS overcommit limits or too many backends.

Steps to resolve 53200:

1. Lower work_mem and maintenance_work_mem — remember work_mem is per sort/hash node per query.
2. Reduce concurrent connections with pooling.
3. Inspect the failing plan for huge in-memory operations; add indexes or rewrite.
4. Check OS vm.overcommit, RAM/swap, and the system log for the OOM killer.

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