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Informix Error -25834: The specified alter fragment operation cannot be performed online.

Cause and resolution

The specified alter fragment operation cannot be performed online.

Online alter fragment is supported only with interval fragmented tables. The following operations can be performed online: - attaching interval fragment - detaching interval fragment - modifying transition value

The following conditions apply for attaching an interval fragment online: - The surviving table has to be an interval fragmented table. - The consumed table has to be non-fragmented. Only one table can be attached at a time. - All indexes on the surviving table has to be fragmented same as table i.e. all indexes must be attached. - For each index on the surviving table, there must be a matching index on the consumed table i.e. index on the same set of columns. - The indexes on the consumed table must be detached and stored in a single dbspace. The dbspace for the index must be same as the dbspace for the consumed table. - If the index on the surviving table is unique, the corresponding matching index on the consumed table must be unique. - The consumed table must have a check constraint that exactly matches the fragment expression being attached and must span a single interval only. This is necessary to ensure no data movement.

The following conditions apply for detaching an interval fragment online: - The surviving table has to be an interval fragmented table. - All indexes on the surviving table has to be fragmented same as table i.e. all indexes must be attached.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-25834 fires when an ALTER FRAGMENT operation not supported online is requested with the ONLINE keyword — per the official guidance, online alter fragment is supported only for interval fragmented tables, and only for attaching an interval fragment, detaching an interval fragment, or modifying the transition value.

  1. An unsupported ALTER FRAGMENT operation requested ONLINE, per the official guidance — the direct, only cause.
  2. For online attach specifically: the surviving table not interval-fragmented, more than one table consumed at once, mismatched/undetached indexes between the surviving and consumed tables, a non-matching unique-index definition, or a missing/mismatched check constraint on the consumed table — per the official guidance, any of these also block the online attach.
  3. For online detach specifically: the surviving table not interval-fragmented, or its indexes not all attached — per the official guidance.
Solutions / Resolution
  1. Perform the operation offline, per the official guidance, if it's not one of the three supported online operations (attach, detach, modify transition value on an interval-fragmented table).
  2. For online attach, satisfy every documented precondition, per the official guidance — matching indexes, unique-index correspondence, a matching check constraint, and single-dbspace detached indexes on the consumed table.
  3. For online detach, confirm all indexes on the surviving table are attached, per the official guidance.
Examples
N/A

No specific triggering statement is documented beyond an unsupported online operation or unmet precondition.

Diagnostic Checks
  1. Check whether the operation is one of the three supported online cases, and, for attach/detach, verify every documented precondition individually.
Related Errors / Related Topics
  • -25845 — "An online operation is already in progress on this table." A related online-operation error, on concurrency rather than operation support.

An ALTER FRAGMENT operation isn't supported online, or an online-attach/detach precondition wasn't met — check the documented list of supported online operations and their preconditions.