SQLSTATE 42501 ERROR

insufficient_privilege permission denied to set parameter “session_preload_libraries” — 42501

PostgreSQL error 42501 — permission denied to set parameter "session_preload_libraries". A statement was rejected because of how it was written or what value it carried — not because of mis

PG 14 · 15 · 16 · 17 · 18 Reviewed Jul 2026

Incident Brief

What happened: A statement was rejected because of how it was written or what value it carried — not because of missing objects or permissions:

ERROR: permission denied to set parameter “session_preload_libraries”

Immediate action: 1. Read the message — it states precisely what PostgreSQL objected to.
2. Have a superuser (or a role granted SET privilege on the parameter via GRANT … ON PARAMETER) change it, or set it in postg

The fix

Copy-paste · works on PG 14–18
  1. Read the message — it states precisely what PostgreSQL objected to.
  2. Have a superuser (or a role granted SET privilege on the parameter via GRANT ... ON PARAMETER) change it, or set it in postgre
Keep going

Related & next steps

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