FDW invalid use of null pointer
SQLSTATE HV009 is raised when a foreign data wrapper implementation uses a NULL pointer internally in an invalid context — this is typically a bug in the FDW extension code.
- 1A bug in a custom FDW C extension that dereferences a NULL pointer
- 2An FDW API callback receives an unexpected NULL value
Buggy FDW extension dereferencing NULL.
expected output
ERROR: FDW: invalid use of NULL pointer
Fix 1
Update the FDW extension to a patched version
WHEN When a third-party FDW is raising HV009.
Why this works
HV009 typically indicates a bug in the FDW code. Check the FDW project issue tracker for known bugs, and upgrade to the latest version or apply a patch.
Fix 2
Add NULL checks in the FDW callback functions
WHEN When developing a custom FDW.
Why this works
In C FDW implementations, validate all pointers received in FDW callback functions (fdw_routines) before dereferencing them.
Class HV — Foreign Data Wrapper Error
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