Informix Error -1831: Combination of FetArrSize, Deferred-PREPARE, and OPTOFC is not supported.

Reasons / Common Causes

-1831 fires when FetArrSize, DEFERRED_PREPARE, and OPTOFC are all enabled together — per the official guidance, this specific three-way combination isn't supported.

1. FetArrSize, DEFERRED_PREPARE, and OPTOFC all active simultaneously, per the official guidance — the direct, only cause.

Solutions / Resolution

1. Disable at least one of FetArrSize, DEFERRED_PREPARE, or OPTOFC, per the official guidance, so the unsupported three-way combination no longer applies.

Examples

N/A

No specific triggering statement is documented — this is a configuration-combination restriction; check which of the three settings can be disabled for the application's actual needs.

Diagnostic Checks

1. Check whether FetArrSize, DEFERRED_PREPARE, and OPTOFC are all enabled, and disable one.

Related Errors / Related Topics

• -1826 — "DESCRIBE information about this statement is not available at this time." A related error, about the interaction of DEFERRED_PREPARE/OPTOFC on DESCRIBE timing rather than an outright unsupported combination.

FetArrSize + DEFERRED_PREPARE + OPTOFC together isn't supported — disable one of the three.