Informix Error -564: Cannot sort rows.

Reasons / Common Causes

-564 is flagged by the official text as an internal error during the sorting phase itself (as distinct from initiating a sort, -566, or reading back already-sorted rows, -565) — the general category of unexpected condition the official guidance describes without a documented application-level trigger.

1. Insufficient temporary space for the sort to complete, a plausible non-engine-internal contributor even though the official text frames this as internal — a large sort running out of room in its configured temp dbspace(s).
2. An I/O error against the temp dbspace backing the sort, surfacing as an unexpected condition mid-sort.
3. A genuine internal engine condition, per the official guidance's framing, with no documented application-level cause.

Solutions / Resolution

1. Check the accompanying ISAM error code, per the official guidance, for the specific underlying reason.
2. Check temporary space availability for the sort, since a large sort exhausting its configured temp space is a plausible concrete cause worth ruling out first:

   onstat -d
   

   reviewing free space in the dbspace(s) named by DBSPACETEMP.
3. If this recurs after ruling out a temp-space shortage, note all circumstances and contact IBM Informix Technical Support, per the official guidance.

Examples

Checking temp space before escalating

$ onstat -d
-- review free-page counts for the dbspace(s) listed in DBSPACETEMP

Diagnostic Checks

1. Check the accompanying ISAM error code first, per the official guidance.
2. Check free space in the DBSPACETEMP dbspace(s) as the most plausible concrete contributor before treating this as purely internal.

Related Errors / Related Topics

• -565 — "Cannot read sorted rows." Same internal-sort-error family, at the read-back stage rather than during the sort itself.
• -566 — "Cannot initiate sort." Same family, at the setup stage rather than during the sort.

Part of a three-error family covering different phases of a sort operation — check the accompanying ISAM error and temp-space availability before escalating.