HV010
PostgreSQLERRORNotableForeign Data Wrapper ErrorHIGH confidence
fdw_function_sequence_error
What this means
A foreign data wrapper callback function was called in the wrong sequence, violating the required FDW execution protocol.
Why it happens
- 1FDW implementation calls IterateForeignScan before BeginForeignScan
- 2EndForeignScan called multiple times without a corresponding BeginForeignScan
- 3FDW code does not follow the required callback invocation order
- 4Bug in FDW code that skips or double-calls lifecycle callbacks
How to reproduce
Foreign table scan execution where FDW callbacks are invoked out of order
trigger — this will error
trigger — this will error
SELECT * FROM my_foreign_table; -- FDW with buggy callback sequencing
expected output
ERROR: HV010: fdw_function_sequence_error
Fix
Update or fix the FDW extension
WHEN FDW extension has a callback sequencing bug
Update or fix the FDW extension
ALTER EXTENSION my_fdw UPDATE;
Why this works
Replaces the buggy FDW code with a corrected version that respects callback order
What not to do
✕ Do not attempt to work around FDW sequence errors by reordering your SQL
The bug is in the FDW C code, not in your SQL; SQL changes will not fix it
Sources
Official documentation ↗
https://www.postgresql.org/docs/current/errcodes-appendix.html
https://www.postgresql.org/docs/current/fdw-planning.html ↗Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev