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Informix Error -320

-320 Not owner of index.

This statement tries to do something, such as dropping an index, that only the owner of the index or a user who has Database Administrator privileges can do. Check that the statement names the index that you intended. If it does, you will have to get its owner or a DBA to execute this statement. See the discussion of error -316 for a way to list the names and owners of indexes.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-320 is the index-level counterpart of -313: an operation requiring index ownership (most commonly DROP INDEX) was attempted by a user who is neither the index's owner nor a database administrator.

  1. Attempting DROP INDEX (or a similarly ownership-gated operation) as a non-owner, non-DBA user — the direct cause.
  2. An index created by a different application/service account than the one currently attempting to drop or modify it.
  3. In an ANSI-compliant database, an index owned by a different user with the same base name as one the current user expected to own — see -319's owner-qualification note.
  4. Confusing table ownership with index ownership — owning the underlying table doesn't automatically grant ownership of every index built on it if a different user created the index.
Solutions / Resolution
  1. Verify the target index and its actual owner, per the official guidance:
    SELECT idxname, tabname, owner FROM sysindexes WHERE idxname = 'idx_orders_customer';
  2. Coordinate with the index owner or a DBA to execute the statement, since ownership can't be bypassed by table ownership alone.
  3. Identify database administrators if the owner is unavailable:
    SELECT username FROM sysusers WHERE usertype = 'D';
Examples
Attempting to drop an index owned by a different user
DROP INDEX idx_orders_customer;
-- -320: the current user isn't the index's owner and isn't a DBA

Fix — find the actual owner first, then have them (or a DBA) run it:

SELECT idxname, owner FROM sysindexes WHERE idxname = 'idx_orders_customer';
-- ask the owner (or a DBA) to run the DROP INDEX
Diagnostic Checks
  1. Confirm the exact index name and its owner via sysindexes.
  2. Confirm the current session's username matches the index's owner, or that the session has DBA privileges.
  3. Don't assume table ownership implies index ownership — check the index's own owner column separately.
Related Errors / Related Topics
  • -313 — "Not owner of table." The table-level counterpart of this same ownership restriction.
  • -319 — "Index does not exist." A related index-reference error — relevant here too since an ANSI-compliant database may need the owner qualifier to even find the right index.

Owning the underlying table doesn't grant ownership of an index another user created on it — check the index's own owner separately before assuming a permission bug.