HV021ERRORTier 2 — Caution✅ HIGH confidence

fdw_inconsistent_descriptor_information

Category: Foreign Data Wrapper ErrorVersions: PostgreSQL 9.1+

What this means

A foreign data wrapper detected inconsistent descriptor information, typically when the column count or types returned by the remote server do not match the expected descriptor.

Why it happens

1Remote table schema changed (column added/removed/retyped) after the foreign table was defined locally
2FDW descriptor built with different column count than actual remote result
3FDW implementation bug — descriptor not properly initialised

How to reproduce

Querying a foreign table whose remote schema has diverged from the local foreign table definition

trigger — this will ERROR

SELECT * FROM my_foreign_table;  -- remote table had columns added/removed

ERROR: HV021: fdw_inconsistent_descriptor_information

Fix 1: Redefine the foreign table to match the remote schema

Remote table schema changed

fix

DROP FOREIGN TABLE my_foreign_table;
IMPORT FOREIGN SCHEMA remote_schema LIMIT TO (my_table) FROM SERVER myserver INTO public;

Why this works

Recreates the foreign table definition to match the current remote schema

What not to do

✗

Do not ALTER the remote table without updating the local foreign table definition

Why it's wrong: Schema drift causes descriptor mismatches

Sources

📚 Official docs: https://www.postgresql.org/docs/current/sql-importforeignschema.html

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

Confidence assessment

✅ HIGH confidence

Standard FDW error code from official PostgreSQL appendix.