Informix Error -795: One or more dbspaces for interval fragments are unusable.

Reasons / Common Causes

-795 is a more serious variant of -794: it fires when a dbspace named in an interval fragmentation STORE IN clause exists but its primary chunk (and mirror chunk, if configured) are unusable — per the official guidance, unlike a simple missing-dbspace situation, this reflects a genuine storage-level problem requiring administrator repair, and the immediate guidance is to roll back and terminate the application rather than retry.

1. A chunk-level hardware or filesystem failure affecting the primary (or mirror) chunk of a dbspace in the STORE IN list, per the official guidance — the underlying condition, though the specific mechanism isn't detailed further.
2. A chunk taken off-line or otherwise made unavailable by an administrative action, with the interval fragmentation mechanism then unable to use it when a new fragment is needed.

Solutions / Resolution

1. Roll back the current transaction and terminate the application, per the official guidance — this is the documented, immediate response, distinct from -794's retry-after-fix pattern.
2. Contact the database server administrator to repair the dbspaces, per the official guidance — this is a storage-level problem outside the scope of application-level recovery.
3. Do not simply retry the operation, since per the official guidance the underlying chunks are unusable, not merely temporarily busy.

Examples

Checking chunk status (for the administrator)

$ onstat -d
-- review chunk status flags for the dbspace(s) named in the interval
-- fragmentation STORE IN clause; look for off-line or down chunks

Diagnostic Checks

1. Roll back and terminate first, per the official guidance, rather than investigating further from the application side.
2. Escalate to the database server administrator, who can check chunk status (onstat -d) and initiate repair.

Related Errors / Related Topics

• -794 — "One or more dbspaces for interval fragments do not exist." A related, less severe STORE IN clause error, about a dbspace not existing at all (fixable via ALTER FRAGMENT or adding the dbspace) rather than an existing dbspace's chunks being unusable.

More serious than -794 — roll back and terminate the application, then escalate to the administrator for chunk repair; don't simply retry.