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Informix Error -942: Transaction commit failed - transaction will be rolled back.

Cause and resolution

Transaction commit failed - transaction will be rolled back.

This error can occur at transaction-commit time if an error is raised when a DataBlade routine calls a UDR-registered end-of-transaction (MI_EVENT_END_XACT) callback. You have registered a callback for the MI_EVENT_END_XACT (or MI_Xact_State_Change) event in the context of a server routine. When the end-of-transaction (MI_EVENT_END_XACT) event occurred to commit the transaction, an error was raised.

Within a DataBlade routine, you can use the mi_error_desc_next() function to obtain the next error, which should explain the cause of the failure. Currently, the end-of-transaction (MI_EVENT_END_XACT) event occurs only within the context of a DataBlade server routine. It does not occur within the context of a DataBlade client application.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-942 fires at transaction-commit time when a DataBlade routine's registered end-of-transaction callback (MI_EVENT_END_XACT, also referred to as MI_Xact_State_Change) itself raises an error during the commit — per the official guidance, this is specific to server-side DataBlade routines that registered such a callback; it doesn't occur in DataBlade client applications.

  1. A registered MI_EVENT_END_XACT callback's own logic raising an error during commit, per the official guidance — the direct, only cause.
  2. A DataBlade routine's end-of-transaction logic encountering a condition it treats as fatal, specific to that DataBlade's own design.
Solutions / Resolution
  1. Use mi_error_desc_next() within the DataBlade routine to obtain the next error, per the official guidance — this should explain the specific cause of the failure, since -942 itself is a generic wrapper around the callback's own raised error.
  2. Consult the documentation for the specific DataBlade involved, since the callback's error logic and its meaning are defined by that DataBlade's own implementation, not the core server.
  3. The transaction is automatically rolled back, per the official guidance's own message text — no separate ROLLBACK WORK is needed; the failed commit already triggers this.
Examples
Retrieving the underlying error within a DataBlade routine
/* Within the callback's error-handling code, call mi_error_desc_next()
   to step through the chained error descriptors and find the one
   describing the actual failure -- consult the DataBlade API Function
   Reference for the exact signature on the server version in use. */
Diagnostic Checks
  1. Use mi_error_desc_next() to retrieve the specific error the MI_EVENT_END_XACT callback raised.
  2. Confirm which DataBlade registered the callback, and consult that DataBlade's own documentation for the error's meaning.
Related Errors / Related Topics
  • -937 — "User Defined Routine error." A related DataBlade/UDR error-wrapper, where the specific cause similarly lives in a value the UDR itself set (SQLSTATE there, versus mi_error_desc_next() here).

A generic wrapper around a DataBlade's own end-of-transaction callback error — use mi_error_desc_next() to find the specific cause; the transaction is already rolled back automatically.