Informix Error -775

Reasons / Common Causes

-775 fires when ALTER FRAGMENT names a partition that doesn't actually have a fragment on the table/index being altered — per the official guidance, partition names default to their dbspace name unless explicitly named at create time, which can make the correct name less than obvious.

1. A misspelled or outdated partition name, per the official guidance's implicit first check — the most likely cause.
2. Assuming a partition's name matches its dbspace name, when it was actually given an explicit name at create time, per the official guidance — the default only applies if no name was specified.
3. A partition that was already dropped/altered, referenced by a name that no longer applies.

Solutions / Resolution

1. Specify a partition that actually has a fragment, per the official guidance.
2. Check the table/index's actual partition names before writing the ALTER FRAGMENT statement:

   SELECT partn, evaltext FROM sysfragments WHERE tabid =
     (SELECT tabid FROM systables WHERE tabname = 'orders') AND fragtype = 'T';
   -- review the fragmentation strategy/partition names for the table
   

3. Remember partition names default to the dbspace name if none was given at create time, per the official guidance — don't assume an explicit name exists without checking.

Examples

An incorrect partition name

ALTER FRAGMENT ON TABLE orders MODIFY west_partition new_dbspace;
-- -775: no fragment on orders is named 'west_partition'

Checking the actual partition names first

SELECT partn, evaltext FROM sysfragments WHERE tabid =
  (SELECT tabid FROM systables WHERE tabname = 'orders') AND fragtype = 'T';
-- find the correct partition name (defaulting to a dbspace name unless
-- explicitly set at create time)

Diagnostic Checks

1. Check the table/index's actual fragment/partition names before retrying, remembering the default-to-dbspace-name rule.

Related Errors / Related Topics

• -772 — "Record/key doesn't qualify for any table/index fragment." A related fragmentation error, about data not matching any fragment rather than a partition name being wrong.
• -773 — "Expression required for new fragment." A related ALTER FRAGMENT error, about a missing expression when adding a fragment.
• -774 — "Cannot specify fragment expressions with a round-robin fragmentation." A related ALTER FRAGMENT restriction, on expressions with round-robin strategy.

Check the table's actual partition names first — they default to the dbspace name unless explicitly set at create time.