Informix Error -9843: Invalid number of arguments for functional key.

Reasons / Common Causes

-9843 fires when a functional key part's argument count is outside the supported range — per the official guidance.

1. A functional key part specifying fewer than 1 or more than 16 arguments, per the official guidance — the direct, only cause.

Solutions / Resolution

1. Use between 1 and 16 arguments for the functional key part, per the official guidance.

Examples

An oversized functional key argument list

CREATE INDEX idx1 ON tab(my_func(c1,c2,c3,...,c17));   -- -9843: 17 arguments

Diagnostic Checks

1. Count the arguments in the functional key's function call, and reduce it to 16 or fewer (and at least 1).

Related Errors / Related Topics

• -9844 — "Invalid function function_name used in a functional key." A related functional-key validity error, on the function itself (e.g. being variant) rather than its argument count.
• -9848 — "Functional key part cannot use a variant function function_name." A related functional-key validity error, specifically on variant functions.

The functional key part had an invalid argument count — use between 1 and 16 arguments.