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Informix Error -778

Cause and resolution

Unable to alter fragmentation scheme on index or table.

During an ALTER FRAGMENT operation, the fragmentation strategy for the index or table could not be altered. See the accompanying ISAM error for more information on why the ALTER FRAGMENT operation failed.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-778 fires when ALTER FRAGMENT can't apply the new fragmentation strategy to the index or table — per the official guidance, the accompanying ISAM error carries the specific reason, the scheme-alteration counterpart to -776's row-move failure.

  1. An underlying ISAM-level error while applying the new fragmentation scheme, per the official guidance's pointer to checking the accompanying ISAM error — the only documented path to the specific cause.
  2. A concurrent operation against the same table/index conflicting with the fragmentation change, a plausible category given similar concurrency-related failures elsewhere.
  3. A malformed or internally-inconsistent new fragmentation scheme, distinct from -776's data-move failure — this error is about the scheme itself not taking effect, not about moving existing rows into an already-accepted scheme.
Solutions / Resolution
  1. Check the accompanying ISAM error code, per the official guidance — the only documented path to the specific underlying cause.
  2. Check for concurrent activity against the table/index at the time of the ALTER FRAGMENT attempt, and retry during a quieter window if contention is suspected.
  3. Review the new fragmentation scheme for internal consistency (expression syntax, dbspace validity, partition naming) before retrying.
Examples
Checking the accompanying ISAM error
-- Review the ISAM error code reported alongside -778 for the specific
-- underlying reason the fragmentation scheme couldn't be applied.
Diagnostic Checks
  1. Check the accompanying ISAM error code first, per the official guidance.
  2. Check for concurrent activity against the table/index.
  3. Review the new fragmentation scheme's own definition for consistency.
Related Errors / Related Topics
  • -776 — "Alter fragment error: unable to move rows to new fragmentation scheme." The closely related row-move-stage failure, once the scheme itself has been accepted.

The scheme-alteration counterpart to -776 — check the accompanying ISAM error and for concurrent activity against the table/index.