Informix Error -161: ISAM error: no TEXT or BYTE field is open.

Reasons / Common Causes

-161 is the direct mirror of -160: instead of isbopen being called twice without an intervening close, this is a TEXT/BYTE manipulation function being called without isbopen having been called first at all. The official text uses the identical framing — "this internal error should not occur" — so the same posture applies: check the one plausible application-level source before treating this as purely an engine-internal condition to escalate.

1. An internal engine-level state inconsistency, per the official text's own framing — not expected to occur through normal engine operation.
2. Application code using ESQL/C-level BLOB APIs directly, calling a TEXT/BYTE manipulation function without a preceding isbopen() call — the direct counterpart mistake to -160's "double open without an intervening close."
3. Complex queries involving TEXT/BYTE columns potentially exposing the same class of internal sequencing edge case as -160, from the other direction.

Solutions / Resolution

1. If this recurs, note all circumstances and contact IBM Informix Technical Support, per the official guidance — the same posture as -160.
2. Review ESQL/C code for isbopen() call ordering, if the affected code path uses low-level BLOB APIs directly — confirm isbopen() always precedes any TEXT/BYTE manipulation function, with no path that skips it.
3. Capture full circumstances for a support case if application-level review of BLOB API usage doesn't reveal a cause — per the official framing, extended independent troubleshooting has limited value beyond this check.

Examples

Reviewing ESQL/C call ordering

/* Wrong: manipulating the field without opening it first */
isbread(fd, buf, len);   /* -161: isbopen() was never called */

/* Right */
isbopen(fd, ...);
isbread(fd, buf, len);
isbclose(fd);

If a code path is found calling a TEXT/BYTE function without a preceding isbopen(), adding the missing call is the fix.

Diagnostic Checks

1. Review whether application code directly uses ESQL/C BLOB API functions, and confirm every TEXT/BYTE manipulation call is preceded by a successful isbopen().
2. Identify the specific query or operation that triggered the error, especially if it involves TEXT/BYTE columns in an unusual way.
3. Capture full circumstances for escalation if the cause isn't found in application-level BLOB API usage.

Related Errors / Related Topics

• -100 — "ISAM error: duplicate value for a record with unique key." The other foundational ISAM-level error in this family.
• -160 — "ISAM error: only one TEXT or BYTE field may be open at any time." The direct mirror-image condition — -160 is calling isbopen twice without closing; -161 is calling a TEXT/BYTE function without ever having called isbopen at all.

Check ESQL/C isbopen()/isbclose() pairing first, exactly as with -160 — it's the one place application code, rather than the engine itself, could plausibly cause this.