Informix Error -21522: No online index build possible

Reasons / Common Causes

-21522 fires when an online index build isn't possible for the requested scenario — per the official guidance, either the index build requires reading rows one by one, or online index builds aren't allowed in the current IDS edition.

1. The index build requiring row-by-row reading, which online build doesn't support, per the official guidance — the first named case.
2. The current IBM Informix Dynamic Server edition not allowing online index builds, per the official guidance — the second named case.

Solutions / Resolution

1. Use a non-online (offline) index build instead when the build requires row-by-row reading, per the official guidance.
2. Check whether the current IDS edition supports online index builds, per the official guidance, and upgrade edition or use an offline build if it doesn't.

Examples

N/A

No specific triggering statement is documented beyond an unsupported online-build scenario or edition.

Diagnostic Checks

1. Check whether the requested index build requires row-by-row reading, and check the current IDS edition's online-index-build support.

Related Errors / Related Topics

• -21515 — "Cannot perform online index build for attached indices." A related online-index-build restriction, specific to attached indices.
• -21521 — "More than 1 online index operation on the same table." A related online-index-build restriction, on concurrent operations rather than build feasibility.

An online index build isn't possible for this scenario or IDS edition — use an offline build instead, or check edition support.