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Informix Error -256

-256 Transaction not available.

You cannot begin a transaction in this database because it does not have a transaction log. In order to support transactions, you must start a transaction log. Refer to your Administrator's Guide for information on how to start a transaction log.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-256 is the SQL-level form of the same condition -122 describes in more depth: the database doesn't have a transaction log, so BEGIN WORK can't be executed at all.

  1. The database was created without transaction logging enabled, and never had logging added since.
  2. An environment mismatch — code developed and tested against a logged database, deployed against an unlogged one.
  3. Logging that was disabled since the application was originally designed.
Solutions / Resolution

See -122 for the full treatment, including the critical sequencing point:

  1. Have the database administrator enable logging, or use START DATABASE ... WITH LOG.
  2. Start logging only immediately after a full backup — per -122's own emphasis, this sequencing isn't optional.
  3. Standardize logging configuration across environments to prevent this kind of mismatch surfacing only in specific deployments.
Examples

See -122's examples for the full backup-then-enable-logging sequence — it applies here without modification.

Diagnostic Checks
  1. Check whether the database has logging enabled:
    SELECT is_logging FROM sysmaster:sysdatabases WHERE name = 'mydb';
  2. Compare configuration across environments if this appeared in one but not another running the same code.
Related Errors / Related Topics
  • -122 — "ISAM error: transaction not available." The fuller treatment of this exact condition — see there for the complete guidance, including the backup-before-logging sequencing requirement.
  • -128 — "ISAM error: no logging." A closely related sibling, reached through a slightly different function but the same underlying missing-logging condition.

This is the same underlying condition as -122 — refer there for the complete guidance.