Informix Error -489

Reasons / Common Causes

-489 fires when GET DIAGNOSTICS (or similar diagnostic-area access) requests an exception number outside the valid range — it must be at least 1 and no greater than the actual number of diagnostic entries currently recorded in the diagnostic area.

1. An exception number of zero or negative — exception numbers are 1-based, so these are never valid.
2. An exception number greater than the actual count of diagnostic entries — the diagnostic area only holds as many entries as the last statement actually generated.
3. A loop iterating over diagnostic entries using a stale or incorrect count, rather than the count from GET DIAGNOSTICS ... NUMBER.

Solutions / Resolution

1. Check the actual number of diagnostic entries first, using GET DIAGNOSTICS :count = NUMBER, before accessing a specific exception number.
2. Iterate from 1 to that count, not an assumed or previously-cached number, when reviewing all diagnostic entries.

Examples

Checking the count before accessing exceptions

GET DIAGNOSTICS :num_exceptions = NUMBER;
-- iterate from 1 to num_exceptions, not a hardcoded or stale value

An out-of-bounds exception number

GET DIAGNOSTICS EXCEPTION 5 :msg = MESSAGE_TEXT;
-- -489 if fewer than 5 diagnostic entries actually exist

Diagnostic Checks

1. Check the diagnostic area's actual entry count via GET DIAGNOSTICS ... NUMBER.
2. Compare the exception number being accessed against that count.

Related Errors / Related Topics

• -472 — "Occurrence value is out of range." A conceptually similar "check the actual count before accessing a specific index" restriction, in the descriptor-occurrence context instead of the diagnostic-area context.

Always check GET DIAGNOSTICS ... NUMBER first — don't assume a fixed or previously-cached diagnostic entry count still applies.