The FDW returned a row descriptor that conflicts with the foreign table definition, so PostgreSQL stops the query.
fdw_inconsistent_descriptor_information (SQLSTATE HV021) occurs when a PostgreSQL foreign data wrapper supplies column metadata that differs from the foreign table definition. Align the foreign table’s column list, data types, and order with what the FDW actually returns, then rerun the query.
fdw_inconsistent_descriptor_information
PostgreSQL raises SQLSTATE HV021 when a foreign data wrapper (FDW) hands back a result descriptor that does not line up with the foreign table’s declared columns. The server cancels the statement to protect data integrity.
The mismatch can be as subtle as a single data-type difference or an omitted column. Fixing the inconsistency restores trusted cross-database reads.
An FDW plugin builds a tuple descriptor at runtime.
PostgreSQL compares that descriptor to the catalog entry created by CREATE FOREIGN TABLE. If any attribute count, order, or data type differs, the check fails and HV021 is thrown.
Schema drifts, manual ALTER FOREIGN TABLE statements, or FDW upgrades commonly introduce the mismatch.
First, inspect the remote data source or FDW code to confirm the exact set of columns and their types. Next, update the foreign table definition so the local catalog mirrors that layout.
Finally, refresh dependent views or materialized views.
Use CREATE OR REPLACE statements inside a transaction to avoid downtime.
Renamed or dropped columns on the remote side often trigger HV021. Re-importing the table with IMPORT FOREIGN SCHEMA or recreating it manually resolves the error.
If you switched from postgres_fdw v1 to v2, new implicit columns may appear.
Recreate the foreign table or specify the column list explicitly in the SELECT to bypass the mismatch.
Lock down DDL on the remote source, or run automated checks that compare information_schema.columns between local and remote tables.
Galaxy’s schema diff viewer highlights column drift early, letting you regenerate the foreign table before production queries fail.
HV020 (fdw_invalid_handle) indicates an invalid cursor handle from the FDW.
HV00N (fdw_invalid_column_name) fires when a column name is unknown. Both are corrected by aligning table definitions and FDW options.
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Columns added, removed, or reordered on the remote database create a mismatch with the local foreign table descriptor.
Developers sometimes change column types locally without updating the FDW or remote schema, leading to descriptor inconsistency.
Newer FDW releases may change the returned descriptor (for example, adding system columns), making existing foreign tables incompatible.
Partial imports or excluding columns during the import step can leave the catalog out of sync when the FDW still returns full rows.
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No. It is a schema mismatch issue, not a role or GRANT problem.
Yes, selecting only the needed columns can temporarily bypass the mismatch, but aligning schemas is the permanent fix.
No. PostgreSQL aborts the statement before any corrupt data can be written.
Galaxy highlights drift between local foreign tables and remote schemas, recommends CREATE or REPLACE statements, and lets you apply them with one click.
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