PG
PRO
HV00MERRORTier 2 — Caution✅ HIGH confidence

fdw_unable_to_create_reply

Category: Foreign Data Wrapper ErrorVersions: PostgreSQL 9.1+

What this means

A foreign data wrapper was unable to create a reply object to receive results from the remote server after initiating query execution.

Why it happens

  1. 1Memory allocation failure when creating the reply structure
  2. 2Remote server closed the connection immediately after execution started
  3. 3FDW implementation error in the reply creation path
  4. 4Protocol mismatch between FDW and remote server version

How to reproduce

FDW query execution when result retrieval infrastructure cannot be created

trigger — this will ERROR
SELECT * FROM my_foreign_table;
ERROR: HV00M: fdw_unable_to_create_reply

Fix 1: Check remote server version compatibility

Protocol mismatch suspected

fix
SELECT version() FROM foreign_version_table;

Why this works

Confirms FDW and remote server are using compatible protocol versions

What not to do

Do not assume the issue is local

Why it's wrong: This error originates at the FDW-to-remote boundary, not in local PostgreSQL

Sources

📚 Official docs: https://www.postgresql.org/docs/current/fdw-error-handling.html

🔧 Source ref: https://www.postgresql.org/docs/current/errcodes-appendix.html

Confidence assessment

✅ HIGH confidence

Standard FDW error code from official PostgreSQL appendix.

See also

📄 Reference pages

Writing a Foreign Data Wrapper
⚙️ This error reference was generated with AI assistance and reviewed for accuracy. Examples are provided to illustrate common scenarios and may not cover every case. Always test fixes in a development environment before applying to production. Spotted an error? Suggest a correction →